A Liftoff only configuration should never tier up to TurboFan, hence add
a proper implication to disable dynamic tiering if --liftoff-only is
set.
Also, add a DCHECK to ensure we never accidentally compile with TurboFan
if --liftoff-only is set.

R=jkummerow@chromium.org

Bug: v8:12281
Change-Id: Ia9b81add503cc939f59fde3f4d3bb67252facf2c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3569741Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79779}