Remove baseline for flaky test.

This test goes back and forth, slightly changing the location of a
rectangle, only on this bot. Remove the baseline so we no longer
see the noise.

Review URL: https://codereview.appspot.com/6460088

git-svn-id: http://skia.googlecode.com/svn/trunk@5087 2bbb7eff-a529-9590-31e7-b0007b416f81