No need to insert into the old-to-shared remembered set for the
shared isolate itself. Check whether the host object is in the shared
isolate before inserting into the remembered set.

Bug: v8:13208, v8:11708
Change-Id: Ic1442653f6c27c51444544cd7b31356594b712e1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3840298
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82574}