When incrementally marking a non-shared heap, shared values should not
be marked. Similarly, non-shared values should not be marked when
incrementally marking a shared heap.

Bug: v8:11708
Change-Id: Iecd799e7e3060e5fb3897b8be0c4e8158d9ff57f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3278673
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77881}