This reverts commit 6747144c.

Reason for revert: https://ci.chromium.org/ui/p/v8/builders/ci/Linux%20V8%20FYI%20Release%20(NVIDIA)/17679/test-results

Original change's description:
> cppgc: Parallel marking in atomic pause
>
> Bug: v8:12424
> Change-Id: I0633e1bd8c890c14ce2c5519253a5e6eb7592f04
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3295580
> Commit-Queue: Omer Katz <omerkatz@chromium.org>
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#78081}

Bug: v8:12424
Change-Id: I8cd6ad8bb72906329bf820a8c1df06e8fa8d89a2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3301469
Owners-Override: Nico Hartmann <nicohartmann@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Auto-Submit: Nico Hartmann <nicohartmann@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78089}