There are currently several flags to tune V8's optimisation level:
  --sparkplug, --maglev, --opt

This CL tries to make this simpler by introducing yet another flag.
--max-opt limits the maximum optimisation tier and avoids the common
error to mistake --no-opt with no dynamic optimisations.

Settings:
  --max-opt=999 Allow all optimisations, default configuration.
                Any number > 3 will do, as long as no other tier will be
                added.
  --max-opt=0   Allow only ignition
  --max-opt=1   Allow up to sparkplug
  --max-opt=2   Allow up to maglev
  --max-opt=3   Allow up to turbofan

Bug: v8:12825
Change-Id: Iff9a0fcccdf05e9770168053a1430303613a7299
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3605816
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Jakob Linke <jgruber@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80418}