Mark new tab tests as flaky.
Mark new tab tests as flaky.

BUG=69940
TEST=new tab failures don't cause build failures
TBR=nsylvain@chromium.org

Review URL: http://codereview.chromium.org/6277008

git-svn-id: http://src.chromium.org/svn/trunk/src@71712 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 2777cc127b2f1060ef6414727aac77175646cc22
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