REF: dont patch assert_frame_equal
This is the only place where we patch assert_frame_equal in the tests.  I think this pattern is pretty useless since it indicates that the relevant EA test wouldn't work for a user who didn't _also_ patch assert_frame_equal.  So we should merge this and then follow up to get rid of the patching-assert_frame_equal pattern altogether.
Thanks @jbrockmendel 