GitLab

 - Remove unflaky test
 - Update bug numbers for web-platform-tests/html/.

BUG=520176,490511
TBR=keishi@chromium.org

Review URL: https://codereview.chromium.org/1297853005 .

git-svn-id: svn://svn.chromium.org/blink/trunk@200797 bbb929c8-8fbe-4397-9dbb-9b2b20218538