This is a reland of 273f4e42

Original change's description:
> [heap] Avoid ParkedMutexGuard during allocation
> 
> Since main thread allocation does not start incremental marking anymore
> while holding allocation_mutex_, background allocation does not need
> ParkedMutexGuard anymore to avoid deadlocks.
> 
> This also means background thread allocation isn't paused anymore to
> perform a GC, which already resulted in subtle bugs (e.g. in
> ExpandBackground with incremental marking). We also do not
> stop-the-world anymore while holding allocation_mutex_.
> 
> Bug: v8:10315
> Change-Id: Iadf00bc26434c765722b82a10497ab06151f15cc
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2289771
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#68754}

Bug: v8:10315
Change-Id: If5aec78370685369ad0f1d7a76002d45f149ddfb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2297468Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68873}