Just a cleanup to remove an unused enum marker.

R=ahaas@chromium.org

Change-Id: I7b40f2389796f43d82d06eb161569ecea7892ef6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2000145Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65753}