Simple experiment that prefers free registers that are not used for
arguments to prevent cases where we allocate a free register without
hint and thereby block later uses of that register for no good
reason.

Bug: v8:8311
Change-Id: I95e96b150410e97937cb72d575ae6bece9ee08f9
Reviewed-on: https://chromium-review.googlesource.com/c/1397668Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Stephan Herhut <herhut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58633}