Disable a test that's failing on the Blink waterfall.

We've already rolled past the Blink revision where it started failing,
so it's not a Blink patch that caused it and restarting/clobbering the
bot did not fix it.

BUG=306318
TBR=jam@chromium.org

Review URL: https://codereview.chromium.org/26953002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228257 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 228257