Team members expressed concerns that "v8_flags" is easier to miss in the
code than the previous "FLAG_" syntax. After a poll and discussions we
decided to rename the struct to "FLAGS", so the new syntax for
addressing flag values is "FLAGS.foo" instead of the previous
"FLAG_foo".

R=cbruni@chromium.org
CC=jkummerow@chromium.org

Bug: v8:12887
Change-Id: I51af4aa7fd5a3b3c29310c0cb4c4ff42086ff012
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3854508
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82701}