Remove the accessibility focus search tests since these APIs are taken out. DO NOT MERGE

1. In JellyBean we have added some APIs to search for next accessibility
   focus in various directions and set accessibility focus from hover.
   However, we have decided that there is not clean answer for how this
   should behave and the APIs were hidden. Now the accessibility service
   is responsible for that. The unused code is now taken out and some
   CTS tests are obsolete.

bug:6773816

Change-Id: I73e879522e15f11b2b7af94dc9a9c89914e49e59