IsRunning() and IsMarking() are now equivalent. So IsRunning() can be
removed in favor of IsMarking().

IsComplete() is also renamed to IsMarkingComplete().

Bug: v8:12775
Change-Id: Ife88be4d674af055590ba5178ec1e410f8fa89d9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3849833Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82665}