If a value is in multiple registers, pick one of them to be freed.

Bug: v8:7700
Change-Id: I1886b977187b4d8e939ff106edde4ccf716661d7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3522063
Auto-Submit: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79463}