Some flag comments and descriptions contained "Turbofan" instead of
"TurboFan".

R=ahaas@chromium.org

Bug: v8:11879
Change-Id: I7e4c6a8820b6ab31eb2f868641a20004faf7104a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2985401Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75385}