Fixed race condition in HBranch::observed_input_representation.

Non-numeric static local variables are not thread-safe, and the case
at hand was a premature optimization anyway: The generated code for
the check in question is exactly the same when unfolded.

BUG=chromium:420483

Review URL: https://codereview.chromium.org/756903003

Cr-Commit-Position: refs/heads/master@{#25502}
harmony-scoping: Catch variable should be VAR, not LET

R=rossberg@chromium.org
BUG=v8:2858
LOG=N

Review URL: https://codereview.chromium.org/748113003

Cr-Commit-Position: refs/heads/master@{#25503}
Force inline Stirng::GetCharVector<>.

R=mvstanton@chromium.org
BUG=chromium:436447

Review URL: https://codereview.chromium.org/756983003

Cr-Commit-Position: refs/heads/master@{#25504}
Move C++ flags for Android to cxxflags section

BUG=v8:3693
R=ulan@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/752063002

Cr-Commit-Position: refs/heads/master@{#25505}
Revert "Distinguish beween final incremental mark-compact and full mark-compact event in IdleNotification."

This reverts commit d15d453fa5aaeeb1f7e010a1baf71e7b3306802b for
breaking cctest/test-api/Threading3.

TBR=hpayer@chromium.org

Review URL: https://codereview.chromium.org/758163003

Cr-Commit-Position: refs/heads/master@{#25506}
Document that Isolate::GetCurrent() must not be called before initialization

Also, add a check for debug mode.

BUG=none
R=dcarney@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/758043002

Cr-Commit-Position: refs/heads/master@{#25507}
[turbofan] Use special constant type for RPO block number operands.

R=dcarney@chromium.org
BUG=

Review URL: https://codereview.chromium.org/758073002

Cr-Commit-Position: refs/heads/master@{#25508}
[x64] Introduce FMA3 instructions on scalar data elements.

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/757503002

Patch from Weiliang Lin <weiliang.lin@intel.com>.

Cr-Commit-Position: refs/heads/master@{#25509}