Remove EventSource tests from OilpanExpectations.

TBR=haraken@chromium.org
BUG=350316
NOTRY=true

Review URL: https://codereview.chromium.org/376823003

git-svn-id: svn://svn.chromium.org/blink/trunk@177663 bbb929c8-8fbe-4397-9dbb-9b2b20218538