If a GC happens between Code object allocation and Code finalization,
we might have invalid embedded object references. We fallback and patch
the refernces back to handles, then unbox the handles and relocate.

Bug: v8:11872
Change-Id: I3a7b050c20179c1708eef343ec8266441ab5dca1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3059689
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75996}