Re-enable TabScrubberTests for SingleProcessMash

BUG=889097
TEST=single_process_mash_interactive_ui_tests
R=sky@chromium.org

Change-Id: If6bc4ffa7c3e97cadf7eb1ce1bdfc371a034e322
Reviewed-on: https://chromium-review.googlesource.com/c/1300757Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Jun Mukai <mukai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602996}

testing/buildbot/filters/chromeos.single_process_mash.interactive_ui_tests.filter

@@ -59,23 +59,5 @@
 -TabDragging/DetachToBrowserTabDragControllerTestTouch.PressSecondFingerWhileDetached/0
 -TabDragging/DetachToBrowserTabDragControllerTestTouch.SecondFingerPressTest/0
 
-# TabScrubber: crbug.com/889097
--TabScrubberTest.Bounds
--TabScrubberTest.CloseBrowser
--TabScrubberTest.DeleteBeforeHighlighted
--TabScrubberTest.DeleteHighlighted
--TabScrubberTest.FullScreenBrowser
--TabScrubberTest.MoveAfter
--TabScrubberTest.MoveBefore
--TabScrubberTest.MoveHighlighted
--TabScrubberTest.Multi
--TabScrubberTest.MultiBrowser
--TabScrubberTest.Repeated
--TabScrubberTest.RTLMoveBefore
--TabScrubberTest.RTLMulti
--TabScrubberTest.RTLSkipped
--TabScrubberTest.Single
--TabScrubberTest.Skipped
-
 # This test is flaky. https://crbug.com/897879
 -ExtensionApiTest.DisplayModeWindowIsInFullscreen