[turbofan] Improve typing of ToBoolean.

According to ES6 draft, revision 29 (2014-12-06), section 7.1.2,
ToBoolean yields true for true, detectable receivers (the ES6 Object
type), symbols and numbers except -0, +0 and NaN.

R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/807663006

Cr-Commit-Position: refs/heads/master@{#25915}
[turbofan] Correctify lowering of Uint8ClampedArray buffer access.

TEST=mjsunit/compiler/regress-444508.js
BUG=chromium:444508
LOG=y
R=machenbach@chromium.org

Review URL: https://codereview.chromium.org/794013004

Cr-Commit-Position: refs/heads/master@{#25916}
Keep AllocationSpace and ObjectSpace enums in sync.

BUG=

Review URL: https://codereview.chromium.org/806693011

Cr-Commit-Position: refs/heads/master@{#25917}
Revert "Retain maps for several garbage collections"

This reverts commit 2bc756e4b36160595c811c5433d0238ae5192525
because of performance regression in kraken.

BUG=chromium:444232
LOG=N
TBR=hpayer@chromium.org

Review URL: https://codereview.chromium.org/816353002

Cr-Commit-Position: refs/heads/master@{#25918}
[turbofan] Materialize the correct kind of constant for bit 1.

Bit 1 should be represented as Int32Constant 1 after simplified
lowering, but OneConstant returns NumberConstant 1.0.

R=jochen@chromium.org, hpayer@chromium.org

Review URL: https://codereview.chromium.org/820993002

Cr-Commit-Position: refs/heads/master@{#25919}
Do not use out of range visitor ids.

BUG=

Review URL: https://codereview.chromium.org/822693002

Cr-Commit-Position: refs/heads/master@{#25920}
Work-around to make webkit test suite work with optdebug==2.

The test driver doesn't know at the moment if optdebug 1 or 2 has been used (the first is used on the bots, the second
locally in quickcheck). It can't know therefore if slow
asserts can be enabled or not. Trying to enable them leads
to a warning if they weren't compiled, which causes webkit
1:1 text comparison to fail.

Review URL: https://codereview.chromium.org/819033002

Cr-Commit-Position: refs/heads/master@{#25921}
[turbofan] Introduce CommonOperatorReducer.

The CommonOperatorReducer currently takes care of redundant Phis,
EffectPhis and Selects. This functionality overlaps with ControlReducer,
but is required to make certain optimizations effective, since the
ControlReducer only runs really early and really late in the pipeline
and therefore other reducers aren't reapplied properly after redundant
phi/select elimination.

TEST=unittests
R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/817243003

Cr-Commit-Position: refs/heads/master@{#25922}
Use weak cell in monomorphic KeyedStore IC.

BUG=v8:3629
LOG=N

Review URL: https://codereview.chromium.org/817873003

Cr-Commit-Position: refs/heads/master@{#25923}
[turbofan] Cleanup use of virtual, OVERRIDE, FINAL.

Following the Google/Chromium coding style wrt. virtual, OVERRIDE and
FINAL specifications.

TEST=unittests
R=jochen@chromium.org

Review URL: https://codereview.chromium.org/816453005

Cr-Commit-Position: refs/heads/master@{#25924}
Implement missing functionality for job based recompilation

BUG=v8:3608
R=bmeurer@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/816363003

Cr-Commit-Position: refs/heads/master@{#25925}