The dead target check in TransitionArrayNeedsCompaction, confirming that
Smi (uninitialized) targets imply that no other target is dead, has to
additionally support Smi entries.

Bug: v8:11305
Change-Id: I6f3fa9e7420b1bd0a64a25dae670f439e3f41162
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2622914
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72040}