This adds accounting for
- StringTable that is marked black directly without going through
  ProcessMarkingWorklist.
- DescriptorArray that is marked black directly inside VisitMap.
- FeedbackMetadata that erroneously was assigned kVisitDataObject
  visitor id, which works only for a fixed size data object.

Bug: chromium:973627
Change-Id: If7c8bca06316f60e975bf86beea09481df8aca8b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2023545Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66006}