After appending 'unimplemented instruction' we need to increase the data
pointer to avoid an endless loop and to fulfill a later DCHECK.

R=jkummerow@chromium.org

Bug: chromium:1201114
Change-Id: I707809f81a4d9a6b3653b94b4836482c006b76ad
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2843819Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74108}