Changes in the reland: Rebased and added a check that JavaScript-linkage
builtins use JSAny in parameters and return type, plus the necessary
cleanups for this test to pass.

Design Doc: https://docs.google.com/document/d/1z6j0pWHnNIfId0v00uWN2HBrGRDJxJfYuCr5K7Kr1xA

This reverts commit 4418a7b9.

Original change's description:
> Revert "[torque] introduce JSAny type for user-accessible JavaScript values"
>
> This reverts commit 79b00555.
>
> Reason for revert: needs more discussion
>
> Original change's description:
> > [torque] introduce JSAny type for user-accessible JavaScript values
> >
> > This CL introduces a JSAny type for user-exposed JavaScript values and
> > a few new types to define it. Especially, it splits Symbol into
> > PrivateSymbol (not exposed) and PublicSymbol (JavaScript exposed
> > symbols).
> >
> > The change is mostly mechanical, but a few things are interesting:
> > - PropertyKey and JSPrimitive were designed to coincide with the spec
> >   notions of IsPropertyKey() and primitive value, respectively.
> > - Since Name is an open type, we define AnyName to be the known
> >   subtypes of Name. This is not too elegant, but by using AnyName
> >   instead of Name, typeswitch can properly conclude something if a
> >   subtype of Name is excluded.
> >
> > Small drive-by changes, which were necessary:
> > - Allow subtyping on label parameters.
> > - Fix the formatting of typeswitch, it was broken with union types
> >   in case types.
> >
> > Bug: v8:7793
> > Change-Id: I14b10507f8cf316ad85e048fe8d53d1df5e0bb13
> > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1735322
> > Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
> > Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#63114}
>
> TBR=neis@chromium.org,jgruber@chromium.org,tebbi@chromium.org
>
> Change-Id: Ifde7881d74afe407628f40047997339d54cb2424
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: v8:7793
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1741652
> Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
> Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#63115}

TBR=neis@chromium.org,jgruber@chromium.org,tebbi@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: v8:7793
Change-Id: Icca34e3824f55009b984d9348fd21884400f0081
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1769316
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63395}

This reverts commit 79b00555.

Reason for revert: needs more discussion

Original change's description:
> [torque] introduce JSAny type for user-accessible JavaScript values
> 
> This CL introduces a JSAny type for user-exposed JavaScript values and
> a few new types to define it. Especially, it splits Symbol into
> PrivateSymbol (not exposed) and PublicSymbol (JavaScript exposed
> symbols).
> 
> The change is mostly mechanical, but a few things are interesting:
> - PropertyKey and JSPrimitive were designed to coincide with the spec
>   notions of IsPropertyKey() and primitive value, respectively.
> - Since Name is an open type, we define AnyName to be the known
>   subtypes of Name. This is not too elegant, but by using AnyName
>   instead of Name, typeswitch can properly conclude something if a
>   subtype of Name is excluded.
> 
> Small drive-by changes, which were necessary:
> - Allow subtyping on label parameters.
> - Fix the formatting of typeswitch, it was broken with union types
>   in case types.
> 
> Bug: v8:7793
> Change-Id: I14b10507f8cf316ad85e048fe8d53d1df5e0bb13
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1735322
> Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#63114}

TBR=neis@chromium.org,jgruber@chromium.org,tebbi@chromium.org

Change-Id: Ifde7881d74afe407628f40047997339d54cb2424
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7793
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1741652Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63115}

This CL introduces a JSAny type for user-exposed JavaScript values and
a few new types to define it. Especially, it splits Symbol into
PrivateSymbol (not exposed) and PublicSymbol (JavaScript exposed
symbols).

The change is mostly mechanical, but a few things are interesting:
- PropertyKey and JSPrimitive were designed to coincide with the spec
  notions of IsPropertyKey() and primitive value, respectively.
- Since Name is an open type, we define AnyName to be the known
  subtypes of Name. This is not too elegant, but by using AnyName
  instead of Name, typeswitch can properly conclude something if a
  subtype of Name is excluded.

Small drive-by changes, which were necessary:
- Allow subtyping on label parameters.
- Fix the formatting of typeswitch, it was broken with union types
  in case types.

Bug: v8:7793
Change-Id: I14b10507f8cf316ad85e048fe8d53d1df5e0bb13
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1735322
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63114}

Use it in String builtins in CSA and String, Array, Object builtins in Torque

Change-Id: I9c828cb1f5f04622470bb71317654cbe09305049
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1680648
Commit-Queue: Z Nguyen-Huu <duongn@microsoft.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62473}

This is a reland of 6eff6cc9

Original change's description:
> [torque] introduce separate implicit parameters for JavaScript calling convention
>
> Implicit parameters for builtins with JavaScript linkage are now separate, using
> the keyword "js-implicit". They have to be one of:
> - context: Context
> - receiver: Object (this in JS)
> - target: JSFunction (arguments.callee in JS)
> - newTarget: Object (new.target in JS)
>
> Bug: v8:9120 v8:7793
>
> Change-Id: I916f60971bb53d5046b6006725d0ce39291ca55e
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1658159
> Reviewed-by: Tamer Tas <tmrts@chromium.org>
> Reviewed-by: Simon Zünd <szuend@chromium.org>
> Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
> Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#62174}

TBR=tmrts@chromium.org

Bug: v8:9120 v8:7793
Change-Id: Idb25d316d9d87e345ab74c2df583ff2648da012c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1660483
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Simon Zünd <szuend@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62182}

This reverts commit 6eff6cc9.

Reason for revert: Presubmit failure.

Original change's description:
> [torque] introduce separate implicit parameters for JavaScript calling convention
> 
> Implicit parameters for builtins with JavaScript linkage are now separate, using
> the keyword "js-implicit". They have to be one of:
> - context: Context
> - receiver: Object (this in JS)
> - target: JSFunction (arguments.callee in JS)
> - newTarget: Object (new.target in JS)
> 
> Bug: v8:9120 v8:7793
> 
> Change-Id: I916f60971bb53d5046b6006725d0ce39291ca55e
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1658159
> Reviewed-by: Tamer Tas <tmrts@chromium.org>
> Reviewed-by: Simon Zünd <szuend@chromium.org>
> Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
> Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#62174}

TBR=sigurds@chromium.org,tebbi@chromium.org,tmrts@chromium.org,szuend@chromium.org

Change-Id: Ide206788745bd15677bd60fe32d2476321967069
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:9120 v8:7793
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1660482Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62175}

Implicit parameters for builtins with JavaScript linkage are now separate, using
the keyword "js-implicit". They have to be one of:
- context: Context
- receiver: Object (this in JS)
- target: JSFunction (arguments.callee in JS)
- newTarget: Object (new.target in JS)

Bug: v8:9120 v8:7793

Change-Id: I916f60971bb53d5046b6006725d0ce39291ca55e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1658159Reviewed-by: Tamer Tas <tmrts@chromium.org>
Reviewed-by: Simon Zünd <szuend@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62174}

This CL adds a lint error for variables that are unnecessarily bound
with 'let' when they could be bound using 'const. This test is skipped
for struct types. For struct types, the "constness" also depends on
the struct methods called and whether these methods write to the struct
or not. This is not straight-forward to detect.

Drive-by: Fix all the newly introduced lint errors.

Bug: v8:7793
Change-Id: I0522ffcc4321350eef2e9573b8430bc78200ddce
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1645322
Commit-Queue: Simon Zünd <szuend@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62085}

Change-Id: I5f0d915351c24b9a2916b8ab1d4bafb4d7eb21c7
Reviewed-on: https://chromium-review.googlesource.com/c/1491217Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59889}

Port String.prototype.endsWith from a CPP builtin to a Torque builtin.

Spec: https://tc39.github.io/ecma262/#sec-string.prototype.endswith
Bug: v8:8400
Change-Id: I4ac8cb92acb68389db844deaecc9ae1c6e7d6bd5
Reviewed-on: https://chromium-review.googlesource.com/c/1454677
Commit-Queue: Simon Zünd <szuend@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59441}