Mark WorkerTest.QueuedSharedWorkerShutdown as flaky on Mac, it times out.
Mark WorkerTest.QueuedSharedWorkerShutdown as flaky on Mac, it times out.

BUG=42641
TBR=atwilson@chromium.org

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@58927 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser