This saves quite some code space on wasm functions, which often do not
spill any tagged values (hence the safepoints will just be empty). It
also often saves a few bytes on code that actually spills tagged values,
but not to the highest frame slots.

R=jkummerow@chromium.org

Bug: v8:11630
Change-Id: I3bd77b3afcd2cf86a92ce5b302b5aa06ec0ed223
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2831873Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74043}