Disable tests that disable threaded compositing on Aura.

Aura always has threaded compositing on.

TBR=piman@chromium.org,fsamuel@chromium.org
BUG=332998

Review URL: https://codereview.chromium.org/167893012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252662 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252662