Suppress a couple of XP-only failures after the vs2013 switch.

These will need baselines too, most likely.

TBR=scottmg@chromium.org
BUG=309197

Review URL: https://codereview.chromium.org/185303004

git-svn-id: svn://svn.chromium.org/blink/trunk@168255 bbb929c8-8fbe-4397-9dbb-9b2b20218538