Move dead bytecode elimination from a seperate bytecode pipeline optimizer
into the BytecodeArrayWriter. This removes the last bytecode pipeline
optimizer, which means we can remove the Bytecode pipeline which,
which should increase compile speed.

BUG=v8:6194

Change-Id: I47fb3c3463b2b8a92e02cf7a6b608683fcfa5261
Reviewed-on: https://chromium-review.googlesource.com/471407
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44568}

Bug: chromium:677032
NOTRY=true

Change-Id: I820e9c89677f4028107719547c372f91e5feb271
Reviewed-on: https://chromium-review.googlesource.com/474805
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44567}

Bug: chromium:705962
NOTRY=true

Change-Id: I734df88af104a9e9800600fee7f41cee5a128450
Reviewed-on: https://chromium-review.googlesource.com/474031Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44566}

Revert of [date] Add ICU backend for timezone info behind a flag (patchset #17 id:320001 of https://codereview.chromium.org/2724373002/ )

Reason for revert:
Breaks noi18n:
https://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20noi18n%20-%20debug/builds/13314

Original issue's description:
> [date] Add ICU backend for timezone info behind a flag
>
> This patch implements a timezone backend which is based on ICU, rather
> than operating system calls. It can be turned on by passing the
> --icu-timezone-data flag. The goal here is to take advantage of ICU's
> data, which is more complete than the data that some system calls expose.
> For example, without any special code, this patch fixes the time zone
> of Lord Howe Island to have a correct 30 minute DST offset, rather than
> 60 minutes as the OS backends assume it to have.
>
> Unfortunately, the parenthized timezone name in Date.prototype.toString()
> differs across platforms. This patch chooses the long timezone name,
> which matches Windows behavior and might be the most intelligible, but
> the web compatibility impact is unclear.
>
> BUG=v8:6031,v8:2137,v8:6076
>
> Review-Url: https://codereview.chromium.org/2724373002
> Cr-Commit-Position: refs/heads/master@{#44562}
> Committed: https://chromium.googlesource.com/v8/v8/+/b213f2399038a615cdfbfa0201cddc113d304018

TBR=ulan@chromium.org,jshin@chromium.org,jgruber@chromium.org,littledan@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:6031,v8:2137,v8:6076

Review-Url: https://codereview.chromium.org/2811103002
Cr-Commit-Position: refs/heads/master@{#44565}

All the optimizations have now been moved to either the BytecodeGenerator
or the BytecodeArrayWriter/Builder.

BUG=v8:6194

Change-Id: Ie5c5d55e824c94ffb503af376c72bc64ad1f6f81
Reviewed-on: https://chromium-review.googlesource.com/469349
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44564}

This fixes {JSCreateLowering} to traverse boilerplate objects in the
same order the runtime uses (i.e. properties first, elements second).
That order is hard-coded in the nesting of {AllocationSite} objects.

R=bmeurer@chromium.org
TEST=mjsunit/regress/regress-crbug-709537
BUG=chromium:709537

Change-Id: I8f446a0880448ea88a3e242e92d11d611581a42b
Reviewed-on: https://chromium-review.googlesource.com/474028Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44563}

This patch implements a timezone backend which is based on ICU, rather
than operating system calls. It can be turned on by passing the
--icu-timezone-data flag. The goal here is to take advantage of ICU's
data, which is more complete than the data that some system calls expose.
For example, without any special code, this patch fixes the time zone
of Lord Howe Island to have a correct 30 minute DST offset, rather than
60 minutes as the OS backends assume it to have.

Unfortunately, the parenthized timezone name in Date.prototype.toString()
differs across platforms. This patch chooses the long timezone name,
which matches Windows behavior and might be the most intelligible, but
the web compatibility impact is unclear.

BUG=v8:6031,v8:2137,v8:6076

Review-Url: https://codereview.chromium.org/2724373002
Cr-Commit-Position: refs/heads/master@{#44562}

Review-Url: https://codereview.chromium.org/2811953003
Cr-Commit-Position: refs/heads/master@{#44561}

Moves the logic for eliding non-effectful accumulator load elision from the
peephole optimizer to the BytecodeArrayWriter.

BUG=v8:6194

Change-Id: I05fbe4ee8ac340e5c355285d0b47e4a9d52fd0a8
Reviewed-on: https://chromium-review.googlesource.com/469828
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44560}

Add support for I32x4Mul, I32x4MaxS, I32x4MinS, I32x4Eq,
I32x4Ne, I32x4Shl, I32x4ShrS, I32x4ShrU, I32x4MaxU,
I32x4MinU, S32x4Select operations for mips32 and mips64
architectures

BUG=

Review-Url: https://codereview.chromium.org/2780713003
Cr-Commit-Position: refs/heads/master@{#44559}

R=danno@chromium.org

Review-Url: https://codereview.chromium.org/2796343002
Cr-Commit-Position: refs/heads/master@{#44558}

Bug: v8:4742
Change-Id: I6f9583cd25c4a8b038e665ea18a20abf29d8b376
Reviewed-on: https://chromium-review.googlesource.com/471107Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Loo Rong Jie <loorongjie@gmail.com>
Cr-Commit-Position: refs/heads/master@{#44557}

IsNumber returns true for Smi/HeapNumber arguments.

IsNumberNormalized expects a number argument and returns true if
it is either a Smi, or a HeapNumber with a value outside the Smi
range.

BUG=

Review-Url: https://codereview.chromium.org/2813623003
Cr-Commit-Position: refs/heads/master@{#44556}

Enable separatio of ic, bytecode, builtin and stub entries through:
    --separate-ic=true
    --separate-bytecodes=true
    --separate-builtins=true
    --separate-stubs=true

Change-Id: I6da4be7add093bb54abe956c60cd186e735ed9b5
Reviewed-on: https://chromium-review.googlesource.com/473046
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44555}

R=clemensh@chromium.org
TEST=mjsunit/asm/call-collisions
BUG=v8:6202

Change-Id: Ie382ed011defb0146c07336b1fd65532ecc20e2e
Reviewed-on: https://chromium-review.googlesource.com/473146Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44554}

* Use BIND, VARIABLE macros everywhere.
* Unify fast path check functions.
* Asserts in CSA::StringCharCodeAt.

BUG=

Review-Url: https://codereview.chromium.org/2811063003
Cr-Commit-Position: refs/heads/master@{#44553}

Bug: chromium:709420
TBR=marja@chromium.org

Change-Id: I71cf02137bcc7d8e163162c6dc1be6b906422281
Reviewed-on: https://chromium-review.googlesource.com/474747Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44552}

This patch implements the runtime semantics of dynamic import.

We create a new ASTNode so that we can pass the JSFunction closure() to
the runtime function from which we get the script_url.

d8 implements the embedder logic required to load and evaluate the modules.

The API is mostly implemented as specified.

BUG=8:5785

Review-Url: https://codereview.chromium.org/2703563002
Cr-Commit-Position: refs/heads/master@{#44551}

According to the spec, section names must be valid UTF-8. This CL adds
a check for that.
Imported and exported names were already checked before.
In order to use the {consume_string} function from the
WasmSectionIterator, it moved it out of the ModuleDecoder into the
anonymous namespace. It now also gets a name for the string to be
parsed, for better error messages.

R=rossberg@chromium.org

Change-Id: I20b1ddb0bd1c7ada237d8303951073310fe1c714
Reviewed-on: https://chromium-review.googlesource.com/470207
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Andreas Rossberg <rossberg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44550}

Other_ID_Start and Other_ID_Continue are not supported by ICU, so for
now we implement these manually as special binary property classes.

R=jgruber@chromium.org
BUG=v8:4743

Review-Url: https://codereview.chromium.org/2808803002
Cr-Commit-Position: refs/heads/master@{#44549}

This reverts commit 751e8935.

Reason for revert: Breaks layout tests:
https://build.chromium.org/p/client.v8.fyi/builders/V8-Blink%20Linux%2064/builds/14885

See:
https://github.com/v8/v8/wiki/Blink-layout-tests

Original change's description:
> [ignition] Add call bytecodes for undefined receiver
> 
> Adds a collection of call bytecodes which have an implicit undefined
> receiver argument, for cases such as global calls where we know that the
> receiver has to be undefined. This way we can skip an LdaUndefined,
> decrease bytecode register pressure, and set a more accurate
> ConvertReceiverMode on the interpreter and TurboFan call.
> 
> As a side effect, the "normal" Call bytecode now becomes a rare case
> (only with calls and super property calls), so we get rid of its 0-2
> argument special cases and modify CallProperty[N] to use the
> NotNullOrUndefined ConvertReceiverMode.
> 
> Change-Id: I9374a32fefd66fc0251b5193bae7a6b7dc31eefc
> Reviewed-on: https://chromium-review.googlesource.com/463287
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#44530}

TBR=rmcilroy@chromium.org,mstarzinger@chromium.org,leszeks@chromium.org,v8-reviews@googlegroups.com,v8-mips-ports@googlegroups.com,v8-ppc-ports@googlegroups.com,v8-x87-ports@googlegroups.com,bmeurer@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Change-Id: I7629dec609d0ec938ce7105d6c1c74884e5f9272
Reviewed-on: https://chromium-review.googlesource.com/474744
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44548}

This reverts commit a79f9031.

Reason for revert: Need to revert:
https://chromium-review.googlesource.com/c/463287/

Original change's description:
> [Interpreter] Unify approach to building interpreter handler and Turbofan stubs.
> 
> Moves interpreter-generator.cc to a similar model of building handlers as
> Turbofan stubs elsewhere, to simplify moving code between stubs / builtins and
> bytecode handlers. This removes the "__" hack from the Interpreter generator
> code.
> 
> Also make SetBytecodeOffset private to InterpreterAssembler and make 
> LdaImmutable[Current]ContextSlot and Lda[Current]ContextSlot share
> handlers since they are identical.
> 
> Change-Id: I9e91e7d37c2ea75513e4dcc3b95b4bb6517f83da
> Reviewed-on: https://chromium-review.googlesource.com/471987
> Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#44534}

TBR=rmcilroy@chromium.org,jkummerow@chromium.org,leszeks@chromium.org,ishell@chromium.org,cbruni@chromium.org,v8-reviews@googlegroups.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Change-Id: I5c72a8a20ab6b8fd862427e1703c883fa484a2c1
Reviewed-on: https://chromium-review.googlesource.com/474745Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44547}

Revert of PPC/s390: [ignition] Add call bytecodes for undefined receiver (patchset #1 id:1 of https://codereview.chromium.org/2809743003/ )

Reason for revert:
Need to revert:
https://chromium-review.googlesource.com/c/463287/

Original issue's description:
> PPC/s390: [ignition] Add call bytecodes for undefined receiver
>
> Port 751e8935
>
> Original Commit Message:
>
>     Adds a collection of call bytecodes which have an implicit undefined
>     receiver argument, for cases such as global calls where we know that the
>     receiver has to be undefined. This way we can skip an LdaUndefined,
>     decrease bytecode register pressure, and set a more accurate
>     ConvertReceiverMode on the interpreter and TurboFan call.
>
>     As a side effect, the "normal" Call bytecode now becomes a rare case
>     (only with calls and super property calls), so we get rid of its 0-2
>     argument special cases and modify CallProperty[N] to use the
>     NotNullOrUndefined ConvertReceiverMode.
>
> R=leszeks@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
> BUG=
> LOG=N
>
> Review-Url: https://codereview.chromium.org/2809743003
> Cr-Commit-Position: refs/heads/master@{#44539}
> Committed: https://chromium.googlesource.com/v8/v8/+/41b228057f89e73fbaae867177d523e60d4e92bc

TBR=joransiu@ca.ibm.com,jyan@ca.ibm.com,leszeks@chromium.org,michael_dawson@ca.ibm.com,bjaideep@ca.ibm.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Review-Url: https://codereview.chromium.org/2809093002
Cr-Commit-Position: refs/heads/master@{#44546}

Before serializing an external string for a native source, we replace
its resource field with the type and index of the native source. Upon
deserialization, we restore the resource.

This change also removes the native source caches with a more straight-
forward mechanism to find the resource type and index.

R=ulan@chromium.org

Review-Url: https://codereview.chromium.org/2807023003
Cr-Commit-Position: refs/heads/master@{#44545}

Rolling v8/build: https://chromium.googlesource.com/chromium/src/build/+log/6c97eff..94c06fe

Rolling v8/third_party/catapult: https://chromium.googlesource.com/external/github.com/catapult-project/catapult/+log/87e8335..9a55aba

Rolling v8/tools/clang: https://chromium.googlesource.com/chromium/src/tools/clang/+log/e9f3127..49df471

TBR=machenbach@chromium.org,vogelheim@chromium.org,hablich@chromium.org

Change-Id: Ie59326de4a9c959e88e604968b6133e9d4677cb8
Reviewed-on: https://chromium-review.googlesource.com/473869Reviewed-by: v8 autoroll <v8-autoroll@chromium.org>
Commit-Queue: v8 autoroll <v8-autoroll@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44544}

Fix error message printed by Runtime_ThrowCalledNonCallable.

As noted on the bug, this has a slight problem in that it will always
print that "asyncIterator" was not callable for GetIterator with an
async IteratorType, though it may be referring to a different call.
This issue is present regardless of the change I introduced to perform
this desugaring in the BytecodeGenerator.

BUG=v8:6187
R=adamk@chromium.org, verwaest@chromium.org

Change-Id: I2077b7cd5976d9d9ba044f0dff44ee8c312d1263
Reviewed-on: https://chromium-review.googlesource.com/470806Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Caitlin Potter <caitp@igalia.com>
Cr-Commit-Position: refs/heads/master@{#44543}

BUG=v8:4614
R=binji@chromium.org,jarin@chromium.org

Review-Url: https://codereview.chromium.org/2799863002
Cr-Commit-Position: refs/heads/master@{#44542}

- Adds WASM opcodes I32x4SConvertI16x8Low, I32x4SConvertI16x8High,
  I32x4UConvertI16x8Low, I32x4UConvertI16x8High, which unpack half of
  an I16x8 register into a whole I32x4 register, with signed or unsigned
  extension. Having separate Low/High opcodes works around the difficulty
  of having multiple output registers, which would be necessary if we unpacked
  the entire I16x8 register.

- Adds WASM opcodes I16x8SConvertI8x16Low, I16x8SConvertI8x16High,
  I16x8UConvertI8x16Low, I16x8UConvertI8x16High, similarly to above.

- Adds WASM opcodes I16x8SConvertI32x4, I16x8UConvertI32x4,
  I8x16SConvert16x8, I8x16UConvertI16x8, which pack two source registers
  into a single destination register with signed or unsigned saturation. These
  could have been separated into half operations, but this is simpler to
  implement with SSE, AVX, and is acceptable on ARM. It also avoids adding
  operations that only modify half of their destination register.

- Implements these opcodes for ARM.

LOG=N
BUG=v8:6020

Review-Url: https://codereview.chromium.org/2800523002
Cr-Commit-Position: refs/heads/master@{#44541}

LOG=N
BUG=v8:6020

Review-Url: https://codereview.chromium.org/2797923006
Cr-Original-Commit-Position: refs/heads/master@{#44536}
Committed: https://chromium.googlesource.com/v8/v8/+/6588187ae3acaa5b40762c539ee9fe355551bea3
Review-Url: https://codereview.chromium.org/2797923006
Cr-Commit-Position: refs/heads/master@{#44540}

Port 751e8935

Original Commit Message:

    Adds a collection of call bytecodes which have an implicit undefined
    receiver argument, for cases such as global calls where we know that the
    receiver has to be undefined. This way we can skip an LdaUndefined,
    decrease bytecode register pressure, and set a more accurate
    ConvertReceiverMode on the interpreter and TurboFan call.

    As a side effect, the "normal" Call bytecode now becomes a rare case
    (only with calls and super property calls), so we get rid of its 0-2
    argument special cases and modify CallProperty[N] to use the
    NotNullOrUndefined ConvertReceiverMode.

R=leszeks@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Review-Url: https://codereview.chromium.org/2809743003
Cr-Commit-Position: refs/heads/master@{#44539}

BUG=

Change-Id: I55e41786f3d249ed545c359589894f39b2d89284
Reviewed-on: https://chromium-review.googlesource.com/437385
Commit-Queue: Ali Ijaz Sheikh <ofrobots@google.com>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44538}

Revert of [ARM] Implement D-register versions of vzip, vuzp, and vtrn. (patchset #4 id:60001 of https://codereview.chromium.org/2797923006/ )

Reason for revert:
Breaks:
http://builders/V8%20Arm%20-%20debug/builds/2751

Original issue's description:
> [ARM] Implement D-register versions of vzip, vuzp, and vtrn.
>
> LOG=N
> BUG=v8:6020
>
> Review-Url: https://codereview.chromium.org/2797923006
> Cr-Commit-Position: refs/heads/master@{#44536}
> Committed: https://chromium.googlesource.com/v8/v8/+/6588187ae3acaa5b40762c539ee9fe355551bea3

TBR=martyn.capewell@arm.com,bmeurer@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:6020

Review-Url: https://codereview.chromium.org/2810703003
Cr-Commit-Position: refs/heads/master@{#44537}

LOG=N
BUG=v8:6020

Review-Url: https://codereview.chromium.org/2797923006
Cr-Commit-Position: refs/heads/master@{#44536}

This was added in commit 40611, but the std::cout calls are gone so the
header is no longer needed.

Remove trailing spaces in html files rom the same commit and from other
html files in the same directory.

Review-Url: https://codereview.chromium.org/2797253009
Cr-Commit-Position: refs/heads/master@{#44535}

Moves interpreter-generator.cc to a similar model of building handlers as
Turbofan stubs elsewhere, to simplify moving code between stubs / builtins and
bytecode handlers. This removes the "__" hack from the Interpreter generator
code.

Also make SetBytecodeOffset private to InterpreterAssembler and make 
LdaImmutable[Current]ContextSlot and Lda[Current]ContextSlot share
handlers since they are identical.

Change-Id: I9e91e7d37c2ea75513e4dcc3b95b4bb6517f83da
Reviewed-on: https://chromium-review.googlesource.com/471987
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44534}

Make sure that the current bytecode's size is taken into account when
updating the interrupt budget (on jumps and returns), so that jumps are
not "free" from an interrupt point of view.

Also clarifies, corrects and cleans up the interrupt budget update for
returns.

Bug: v8:6238
Change-Id: I1099d53a232fab4c1fcc91115baee610bfbce1d6
Reviewed-on: https://chromium-review.googlesource.com/472809Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44533}

It's possible to get undefined as a result of Object.getOwnPropertyDescriptor. We should be ready for this.

BUG=chromium:707670
R=alph@chromium.org

Review-Url: https://codereview.chromium.org/2801763002
Cr-Commit-Position: refs/heads/master@{#44532}

We assumed that every JSArray would have a JSObject as a prototype,
but it could be null, in which case we bail out to slow path.

Also rename spread_array variable here, because this fast-path
isn't just used by spreads anymore.

Bug: chromium:707675
Change-Id: I8045d83977735dd00c3ebde2e0704f6b04afdedd
Reviewed-on: https://chromium-review.googlesource.com/472907Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44531}

Adds a collection of call bytecodes which have an implicit undefined
receiver argument, for cases such as global calls where we know that the
receiver has to be undefined. This way we can skip an LdaUndefined,
decrease bytecode register pressure, and set a more accurate
ConvertReceiverMode on the interpreter and TurboFan call.

As a side effect, the "normal" Call bytecode now becomes a rare case
(only with calls and super property calls), so we get rid of its 0-2
argument special cases and modify CallProperty[N] to use the
NotNullOrUndefined ConvertReceiverMode.

Change-Id: I9374a32fefd66fc0251b5193bae7a6b7dc31eefc
Reviewed-on: https://chromium-review.googlesource.com/463287
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44530}

Reland of Ensure counters are initialized, to avoid init on non-joinable threads. (patchset #1 id:1 of https://codereview.chromium.org/2812653002/ )

Reason for revert:
Appears to be a flake. Both jgruber and I tried to repro locally and failed. Also change has little change of having had caused those failures.

Original issue's description:
> Revert of Ensure counters are initialized, to avoid init on non-joinable threads. (patchset #1 id:1 of https://codereview.chromium.org/2812543002/ )
>
> Reason for revert:
> https://build.chromium.org/p/client.v8/builders/V8%20Linux64%20-%20gyp/builds/5221
>
> Original issue's description:
> > Ensure counters are initialized, to avoid init on non-joinable threads.
> >
> > This occurs in the wasm scenario described in the referenced bug.
> > DecodeWasmModule collects statistics. Blink inserts a CreateHistogramCallback that
> > can't instantiate a histogram on non-joinable threads. Turns out, DecodeWasmModule
> > is scheduled on such a thread, now that we have async compilation.
> >
> > This fix pre-initializes histograms when the callback is applied, which is assumed to
> > be in a context that can carry out the instantiation. In Blink, this happens on the main
> > thread.
> >
> > BUG=chromium:709684
> >
> > Review-Url: https://codereview.chromium.org/2812543002
> > Cr-Commit-Position: refs/heads/master@{#44522}
> > Committed: https://chromium.googlesource.com/v8/v8/+/022e7ddf232b0696eb595769fa702463c417db5e
>
> TBR=jochen@chromium.org,mtrofin@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=chromium:709684
>
> Review-Url: https://codereview.chromium.org/2812653002
> Cr-Commit-Position: refs/heads/master@{#44527}
> Committed: https://chromium.googlesource.com/v8/v8/+/038bafcb8c0435bc4130228237124331295d4713

TBR=jochen@chromium.org,jgruber@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:709684

Review-Url: https://codereview.chromium.org/2813673002
Cr-Commit-Position: refs/heads/master@{#44529}