Skip unhandled promises for AsyncAwait performance test.

Bug: v8:1099632
Change-Id: I21d69d5700860f0b05fb8c6c90ea85dc28cb3890
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2274606Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68631}

This slows down promise benchmarks since we process all unhandled promises.

Bug: vu:1099632
Change-Id: I2188a2842ec0a69ca93e5d406f10371ceff60f9b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2270235Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68575}

This replaces Runtime_RunMicrotasks with Runtime_PerformMicrotaskCheckpoint.

RunMicrotasks forcibly runs Microtasks even when the microtasks are suppressed,
and may causes nested Microtasks in a problematic way. E.g. that confuses
v8::MicrotasksScope::IsRunningMicrotasks() and GetEnteredOrMicrotaskContext().

OTOH, PerformMicrotaskCheckpoint() doesn't run cause the failure as it
respects the microtask suppressions.

As all existing tests don't call RunMicrotasks() in the suppressed situation
(like Promise.resolve().then(()=>{%RunMicrotasks();})), this change should
not affect to these tests.

Change-Id: Ib043a0cc8e482e022d375084d65ea98a6f54ef3d
Reviewed-on: https://chromium-review.googlesource.com/c/1360095Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Taiju Tsuiki <tzik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58068}

These benchmarks are intended to compare the overhead of async-await vs.
a naive promise implementation vs. the babel async-await transformation.
The functions in the benchmark don't do any work themselves, so results
should reflect only overhead of the chosen implementation.

Current numbers on my local machine (higher is better):

BaselineES2017-AsyncAwait(Score): 2006
BaselineNaivePromises-AsyncAwait(Score): 7470
Native-AsyncAwait(Score): 3640

BUG=v8:5639

Review-Url: https://codereview.chromium.org/2577393002
Cr-Commit-Position: refs/heads/master@{#41860}