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: http://src.chromium.org/svn/trunk/src@58927 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: ebe56b2bcf23e18afe2db0bdedbf907c3531412c
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser