for in the register allocation.

NOTE: This is expected to cause performance regressions, but we enable
it so that we can land small tweaks on top of it and get immediate
performance feedback.

Change-Id: I062f98a3ee6702509e870cc110096a3bdf53a6fd
Bug: v8:9088
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1681133
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Auto-Submit: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62447}