Merge changes from topic "re-revert move sched_policy functions"

* changes:
  DO NOT MERGE: Revert "Revert "Add dependencies on libprocessgroup for sched_policy users""
  DO NOT MERGE: Revert "Revert "libcutils: Move sched_policy functions into libprocessgroup""
  DO NOT MERGE: Revert "Revert "Add libprocessgroup into VNDK""