Reland of Fix async/await memory leak (patchset #1 id:1 of https://codereview.chromium.org/2354473002/ )

Reason for revert:
Relanding with faster-running test

Original issue's description:
> Revert of Fix async/await memory leak (patchset #5 id:80001 of https://codereview.chromium.org/2334323006/ )
>
> Reason for revert:
> newly introduced test async-await-loop times out: https://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20arm64%20-%20sim%20-%20MSAN/builds/10894/steps/Ignition%20-%20turbofan%20%28flakes%29/logs/async-await-loop
>
> Original issue's description:
> > Fix async/await memory leak
> >
> > This patch closes a memory leak in async/await where the desugaring
> > was creating a situation analagous to that described in v8:5002.
> > Intermediate Promises were being kept alive, so a long-running loop
> > would cause linear memory usage on the heap. This patch returns
> > undefined to the 'then' callback passed into PerformPromiseThen
> > in order to avoid this hazard. Test expectations are fixed to remove
> > expecting extraneous events which occurred on Promises that are
> > now not given unnecessarily complex resolution paths before being
> > thrown away.
> >
> > BUG=v8:5390
> >
> > Committed: https://crrev.com/a0ba18e9634c5e2d439033ab61a77cff54f9af35
> > Cr-Commit-Position: refs/heads/master@{#39479}
>
> TBR=adamk@chromium.org,caitp@igalia.com,littledan@chromium.org
> NOTRY=true
> BUG=v8:5390
>
> Committed: https://crrev.com/196db1999da130019bbf8e3bd65977f840e8afaf
> Cr-Commit-Position: refs/heads/master@{#39493}

TBR=adamk@chromium.org,caitp@igalia.com,hablich@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
BUG=v8:5390

Review-Url: https://codereview.chromium.org/2348403002
Cr-Commit-Position: refs/heads/master@{#39508}