Revert of Gardening: Mark two failing virtual/threaded/animations tests as failing (https://codereview.chromium.org/269573009/)

Reason for revert:
The tests are passing again.

Original issue's description:
> Gardening: Mark two failing virtual/threaded/animations tests as failing
> 
> BUG=369330
> TBR=falken@chromium.org
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=173133

TBR=falken@chromium.org,jsbell@chromium.org
NOTRY=true
BUG=369330

Review URL: https://codereview.chromium.org/266213002

git-svn-id: svn://svn.chromium.org/blink/trunk@173309 bbb929c8-8fbe-4397-9dbb-9b2b20218538