We need to exit before FallThruTo invokes DCHECK(this->ok()).

Bug: chromium:1194316
Change-Id: I77eb58cbe232277cc8fc3cc0d1c327d7eba8bfb3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2796954Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73742}