This is a reland of 80f10346

Original change's description:
> Reland "heap: Use generic flags for main-thread only flags"
>
> This is a reland of 2a8e2a9b
>
> Original change's description:
> > heap: Use generic flags for main-thread only flags
> >
> > BasicMemoryChunk flags should only be mutated from the main thread
> > when no concurrent task can access them. For that purpose it is enough
> > to use regular non-atomic flags as they are immutable while the GC is
> > running.
> >
> > Change-Id: I0a9f8ecb2eb2aafaf17e77626ae27604abd1b618
> > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3107230
> > Reviewed-by: Hannes Payer <hpayer@chromium.org>
> > Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
> > Cr-Commit-Position: refs/heads/main@{#76471}
>
> Change-Id: Iaf495546f82291ab674537f5d39e10d0495ac612
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3117486
> Auto-Submit: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Hannes Payer <hpayer@chromium.org>
> Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#76506}

Change-Id: I662bccdf94fc53efcdd209f85d6b044786dee250
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3123412
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Auto-Submit: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76528}