Mark StartupTest.PerfSeveralTabs as flaky on Win.
Mark StartupTest.PerfSeveralTabs as flaky on Win.

BUG=46609
TEST=Should turn green!
Review URL: http://codereview.chromium.org/5460001

git-svn-id: http://src.chromium.org/svn/trunk/src@67895 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: cc215f68478d43e6d45eec43e7e099e4f600d113
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