Fix Promise.resolve/Promise.reject unnecessarily scheduling a microtask.

R=rossberg@chromium.org, yangguo@chromium.org, adamk@chromium.org
LOG=N

Review URL: https://codereview.chromium.org/777703002

Cr-Commit-Position: refs/heads/master@{#25650}
Fix path construction in perf runner.

BUG=chromium:374740
LOG=n
TEST=python -m unittest run_perf_test
TBR=ulan@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/776873005

Cr-Commit-Position: refs/heads/master@{#25651}
Encode reservation meta data in the snapshot blob.

This also makes reserving multiple chunks per object space possible.

R=vogelheim@chromium.org

Review URL: https://codereview.chromium.org/781443002

Cr-Commit-Position: refs/heads/master@{#25652}
[x64] check sahf correctly

BUG=

Review URL: https://codereview.chromium.org/777173002

Cr-Commit-Position: refs/heads/master@{#25653}
Revert of Encode reservation meta data in the snapshot blob. (patchset #3 id:40001 of https://codereview.chromium.org/781443002/)

Reason for revert:
[sheriff] Breaks http://build.chromium.org/p/client.v8/builders/V8-Blink%20Linux%2064/builds/1540

Original issue's description:
> Encode reservation meta data in the snapshot blob.
>
> This also makes reserving multiple chunks per object space possible.
>
> R=vogelheim@chromium.org

TBR=vogelheim@chromium.org,baixo@chromium.org,yangguo@chromium.org
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/780833002

Cr-Commit-Position: refs/heads/master@{#25654}