Clean up a few more tests that always pass.

This is cribbed from @dpranke's https://codereview.chromium.org/24250007/,
so I can't claim credit for them.

TBR=dpranke
BUG=

Review URL: https://codereview.chromium.org/26162006

git-svn-id: svn://svn.chromium.org/blink/trunk@159054 bbb929c8-8fbe-4397-9dbb-9b2b20218538