Label already supports forward references through the label itself, so
we don't need to keep track of that separately.

Change-Id: I16fd10888041c833e1c65ffdaaa985a7adf8c126
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3790975
Auto-Submit: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82039}