http/tests/images/image-with-origin-header.html is flaky.

BUG=341435
TBR=zmo@chromium.org

Review URL: https://codereview.chromium.org/197053003

git-svn-id: svn://svn.chromium.org/blink/trunk@169179 bbb929c8-8fbe-4397-9dbb-9b2b20218538