Disable DumpAccessibilityEventsTest.AccessibilityEventsExpandedChange on Mac

The test fails a DCHECK introduced in crrev.com/c/1593403.

TBR=atotic@chromium.org

Bug: 985925
Change-Id: Id50178579db8aefc3b0e1ae97ab943fa7941a351
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1710899
Reviewed-by: Yi Gu <yigu@chromium.org>
Reviewed-by: Aleks Totic <atotic@chromium.org>
Commit-Queue: Yi Gu <yigu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#679276}
1 file changed