When picking an arbitrary register for an input, prefer picking a
register that's already used as input. If there's no such register,
block the newly picked register.

Bug: v8:7700
Change-Id: I5926ae33482aa615060fef3500c1d2d6079090a4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3716476
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Auto-Submit: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81276}