Rebaseline web-animations-css failures.

Our goal is to have TestExpectations be empty. As such, lines in
TestExpectations are not the right way to track test failures, bugs
are.

BUG=274667
TBR=dstockwell@chromium.org

Review URL: https://codereview.chromium.org/23060014

git-svn-id: svn://svn.chromium.org/blink/trunk@156242 bbb929c8-8fbe-4397-9dbb-9b2b20218538