Update notion of compatibility used in redundancy elimination
to determine whether one check subsumes another check to ignore
the feedback on the operator.

Bug: v8:7127
Change-Id: I77ab8a64adcd2b36ee7eafbe6cc148ddbc430b11
Reviewed-on: https://chromium-review.googlesource.com/839441
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50318}