Off heap members are "safe" to reference dead objects since they are not
connected to the object graph and do not ressurect the object.

This is needed becuase Members are used as temporary on stack variables
in Blink, e.g. when querying if a HeapHashMap contains a key.

Bug: v8:11749
Change-Id: I7ab2559d00c366480a3efbc0512bb1d1f63b64e7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3182223Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77063}