- The fallback path for "digit_mul" was missing shifts
- RightTrim() could end up reading digit(-1) (i.e. the bit field)
- Add SLOW_DCHECKs to digit()/set_digit() to catch any further
  invalid-index issues

Bug: v8:6791
Change-Id: I901edfce90bb6ac11e74c3c3f577225f12bad177
Reviewed-on: https://chromium-review.googlesource.com/683796Reviewed-by: Daniel Ehrenberg <littledan@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48193}

Bug: v8:6791
Change-Id: I2da258f7db6c74d764c674eb8d550418a566c5ea
Reviewed-on: https://chromium-review.googlesource.com/662138
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48002}

BigInt is a new primitive type of arbitrary precision integers,
proposed in https://tc39.github.io/proposal-bigint.

This CL introduces a corresponding instance type, map, and C++
class to V8 and adds BigInt support to a few operations (see the
test file). Much more is to come. Also, the concrete representation
of BigInts is not yet fixed, currently a BigInt is simply a wrapped
Smi.

Bug: v8:6791
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: Ia2901948efd7808f17cfc945f0d56e23e8ae0b45
Reviewed-on: https://chromium-review.googlesource.com/657022Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47956}

Only the CompilationCache doesn't actually specialize the table to the point where it knows how to hash stored keys. This moves the virtual HashForObject down from HashTableKey to CompilationCacheKey, and moves previous virtual implementations to the respective shapes.

Bug: v8:6474
Change-Id: I0a1ae26a224d602d16692d2b09c96a2ab193f07f
Reviewed-on: https://chromium-review.googlesource.com/529110Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45842}

BUG=v8:5402
R=mstarzinger@chromium.org

Change-Id: I8ce43504fee83dcb6859418a526b2c7aea52e778
Reviewed-on: https://chromium-review.googlesource.com/468968
Commit-Queue: Marja Hölttä <marja@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44436}