chromeos: disables OverviewSessionTest.RoundedEdgeMaskVisibility

This test leaks WindowMirrorViews. While this isn't a problem in existing
code, it does cause a problem with a patch I have out for review. I'm going
to disable now and track down the leak separately.

BUG=941048
TEST=test only change

Change-Id: I1d429f006d353a449c7a9cc40bcc0c4aad99837b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1518070
Reviewed-by: Jun Mukai <mukai@chromium.org>
Reviewed-by: Sammie Quon <sammiequon@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#640029}
1 file changed