Restore an original flakiness expectation after rebaseline

BUG=377013
TBR=wangxianzhu@chromium.org

Review URL: https://codereview.chromium.org/385963007

git-svn-id: svn://svn.chromium.org/blink/trunk@178085 bbb929c8-8fbe-4397-9dbb-9b2b20218538