Mark compositing/video/video-reflection.html as failing

TBR=steveblock@chromium.org
BUG=324370

Review URL: https://codereview.chromium.org/95883003

git-svn-id: svn://svn.chromium.org/blink/trunk@162861 bbb929c8-8fbe-4397-9dbb-9b2b20218538