This reverts commit c84963eaa7.
Reason for revert: Fails on msan: https://ci.chromium.org/p/v8/builders/ci/V8%20Linux%20-%20arm64%20-%20sim%20-%20MSAN/31376
Original change's description:
> [heap] Introduce safepoint mechanism
>
> Add safepoint mechanism to stop concurrent threads and bring them to a
> safepoint. Threads are stopped before the safepoint and after e.g. the
> GC resumed again. Each thread needs to be stopped in a safepoint, such
> that all roots can be iterated safely.
>
> Running threads need to be cooperative and are required to perform
> regular safepoint polls.
>
> Bug: v8:10315
> Change-Id: I47f07e7d2ef5bc5adbba6b9e8e79a1f0f45b97ad
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2102578
> Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#66727}
TBR=ulan@chromium.org,dinfuehr@chromium.org
Change-Id: If11281b2b9fc622b91261417b202676f23f60b50
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:10315
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2105634
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66729}
81d8e42f91