Merge changes from topics "vpnmove-getconnectionowneruid", "vpnmove-systemdefaultcallback", "vpnmove-vpntransportinfo"

* changes:
  Accept both pre-S and post-S errors in getConnectionOwnerUid.
  Add CTS coverage for VpnTransportInfo.
  Add test coverage for registerSystemDefaultNetworkCallback.
tree: cfac0100cfd3a836cb9b398514e9698f3f9ef079
  1. tests/
  2. Tethering/
  3. .gitignore
  4. OWNERS
  5. PREUPLOAD.cfg
  6. TEST_MAPPING