ObjectSizeTrait::GetSize is used by Trace methods in Blink and may be
called while concurrent marking is active. The current version is
non-atmoic and therefore can race with marking on other threads.

Bug: chromium:1261860
Change-Id: Ia0b41ec496ac64ae3dd5a040b25f6972b21561c5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3240832Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77527}