The atomic pause would not report any marked bytes which in turn would
mean that the used bytes counter would stay at 0 for testing GCs that
always use atomic marking.

Bug: chromium:1056170
Change-Id: Ie35d9b3bc88766c4ef56271f05d944f4835ba431
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2704662
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72850}