Remove tests that are no longer flaky.

This side of the yak is shaved.

BUG=307570
R=tony

Review URL: https://codereview.chromium.org/37513003

git-svn-id: svn://svn.chromium.org/blink/trunk@160370 bbb929c8-8fbe-4397-9dbb-9b2b20218538