Disable a bunch of policy-related tests that started failing a while ago.

I tried reverting several changes first (see BUG), but didn't find the right
one.  The consistent failures suggest that this feature is broken, so this
needs to be investigated by someone familiar with this code.

BUG=330454
TBR=skuhne@chromium.org,mnissler@chromium.org

Review URL: https://codereview.chromium.org/120563002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242326 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242326