'override' implies 'virtual', thus 'virtual' should be skipped.

R=mlippautz@chromium.org

Bug: v8:11717
Change-Id: If5e9c2aeec85fcf0832f9712b6e09752c4d2c2d3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2878737Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74432}