From the concurrent compiler's perspective, we can perform those
read/writes non-atomically and have wider TSAN coverage. The concurrent
marker, however, needs them to be atomic.

Bug: v8:7790
Change-Id: I96897f4f6237c90da018ec89be838aae894c24bc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2817538
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73935}