TestExpectations for handful of tests flakily hitting assert

Unreviewed gardening. They've been like this for a while now.

BUG=310323
TBR=dpranke@chromium.org

Review URL: https://codereview.chromium.org/36113002

git-svn-id: svn://svn.chromium.org/blink/trunk@160255 bbb929c8-8fbe-4397-9dbb-9b2b20218538