Remove some stale lines from TestExpectations.

Linux Aura is long-shipped and the bug is marked fixed.

BUG=318980
TBR=dpranke@chromium.org

Review URL: https://codereview.chromium.org/376263003

git-svn-id: svn://svn.chromium.org/blink/trunk@177790 bbb929c8-8fbe-4397-9dbb-9b2b20218538