The old "gc-safe" implementation to get the off-heap type information
wasn't quite as gc-safe as it needs to be.
Due to parallel compaction, we shouldn't check for forwarding pointers;
instead we should rely on the old location of the Foreign, but make sure
not to look at its Map (which might be a forwarding pointer).

Bug: v8:12185
Change-Id: I4570b00a5300a0d7ed8c042fa21d355373e0e691
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3260513
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77707}