Disable OptionsWebUITest.OverlayShowDoesntShift on win.

Sheriff: it's flakily timing out regularly on windows.
http://chromium-build-logs.appspot.com/gtest_query?gtest_query=OptionsWebUITest.OverlayShowDoesntShift

TBR=pam

BUG=315250

Review URL: https://codereview.chromium.org/68933005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234289 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234289