omnibox: Remove unregistered NOTIFICATION_BOOKMARK_MODEL_LOADED from action_box test.

BUG=144783
R=sky@chromium.org


Review URL: https://chromiumcodereview.appspot.com/12038057

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@178760 0039d316-1c4b-4281-b951-d872f2087c98