This is a reland of 86038ecf

Compared to the previous CL this one is adding a TSAN suppression
for GlobalSafepoint::EnterSafepointScope. local_heaps_mutex_ of client
isolates may be locked in any order. This would be detected by TSAN as a
potential race. Add some additional DCHECKs to compensate for that
missing test coverage.

As a cleanup this CL also removes the unused methods ContainsLocalHeap()
and ContainsAnyLocalHeap() from LocalHeap.

Original change's description:
> [heap] Optimize time to reach global safepoint
>
> Initial support for global safepoints kept it simple by entering a
> safepoint for each of them one after another. This means
> time-to-global-safepoint is the sum of all time-to-safepoint operations.
> We can improve this slightly by splitting up the safepoint iteration
> into two operations:
>
> 1) Initiate safepoint lock (locks local_heaps_mutex_, arms the barrier
>    and sets SafepointRequested flag for all client threads)
> 2) Block until all runnning client threads reach a safepoint
>
> We now perform operation 1) for all clients first and only then start
> with operation 2).
>
> Bug: v8:11708
> Change-Id: Iaafd3c6d70bcf7026f722633e9250b04148b3da6
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3310910
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#78308}

Bug: v8:11708, v8:12492
Change-Id: I7087ba23c08f2d4edb9b632eef3c218fc76342e7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3328786Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78583}