Removing hierarchical accessibility focus directions.

1. The accessibility focus directions are not needed since an
   accessibility service just get the root, first child, next
   sibling, previous sibling and call execute the action to
   give it accessibility focus. Now the accessibility node
   info tree is properly ordered taking into account layout
   manager directions for both layout manager that we report
   and ones that we have determined as not important for
   accessibility. Also the position of a node info are ordered
   properly based on their coordinates after all transformations
   as opposed to child index.

bug:5932640

Change-Id: I994a8297cb1e57c829ecbac73a937c2bcbe0bac7