We did not handle conflicts between regular register moves and the
cached instance / cached memory start correctly. This could lead to us
overwriting a regular register when restoring the cached instance, which
results in either crashes or miscalculations afterwards.

R=ahaas@chromium.org

Bug: chromium:1217064
Change-Id: Icd4b08b97a47726108a50d51b3a7ba410d132f98
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3003158Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75602}