Young generation collection requires that full GCs unmark before
starting marking.

Bug: v8:12324
Change-Id: Id6cc218057252cbf0664326126f34b07ac8ea247
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3229570
Auto-Submit: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77445}