Disable AppWindowAPI.TestRestoreGeometryCacheChange on Mac

Flaky failures, see bug

BUG=324915
TEST=browser_tests
R=asargent@chromium.org

Review URL: https://codereview.chromium.org/101613004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238497 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238497