The heap snapshot view in the dev tools reports a lot of incorrect
retaining paths involving weak references from FeedbackVectors. To fix,
when IndexedReferencesExtractor encounters a weak reference, it should
record a weak reference rather than a hidden reference. This way, the
forward reference is still visible when exploring in the summary view,
but weak references aren't reported as retainers.

Bug: v8:12112
Change-Id: Ib3bafc49482fb4f515877a90bae8707483d0a7a2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3101266Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#76364}