Merge changes I044d0363,I0be3b802,Ib584ea57,I92291023

* changes:
  bpf is required so /sys/fs/bpf/map_netd_app_uid_stats_map always exists
  bpf is required - remove mUseBpfTrafficStats field
  bpf is required - remove checkBpfStatsEnable()
  remove qtaguid parsing