As a preparation to add a "boolean validation" mode, rename the existing
flags. This removes many unrelated changes from the follow-up change and
makes it easier to review.

R=thibaudm@chromium.org

Bug: v8:10969
Change-Id: I5f71405b525a7caa91be46c035e31d4d960e4e4c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2440036Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70224}