This changes TurboFan to treat SignedSmall feedback similar to Signed32
feedback for binary and compare operations, in order to simplify and
unify the machinery.

This is an experiment. If this turns out to tank performance, we will
need to revisit and ideally revert this change.

Bug: v8:7094
Change-Id: I885769c2fe93d8413e59838fbe844650c848c3f1
Reviewed-on: https://chromium-review.googlesource.com/c/1261442Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56411}