In order to make the shared code write barrier thread-safe, we simply
lock the page mutex when appending to the typed_slot_set. We can later
improve this when performance isn't good enough.

Bug: v8:13018
Change-Id: I5e12f83f459f8976c22ec488cfa9b6f16d4a8a8e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3763867Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81855}