Merge changes I6ec246a6,If7eb8857,Id3d12b23,Ia52f9caf,I21028457, ... into rvc-dev

* changes:
  Fix legacy APIs when VPN switches to suspended underlying network.
  Backport test coverage from aosp/1547496.
  Backport some helpers in ConnectivityServiceTest.
  Test for bugs with suspended VPN underlying networks.
  Add a test for getDefaultNetworkCapabilitiesForUser.
  Improve testing of CONNECTIVITY_ACTION broadcasts.
  Test passing an underlying network array with null network in it.
  Make testVpnNetworkActive more deterministic.
  Make MockVpn more realistic and easier to use.
  Increase test coverage for VPN info sent to NetworkStatsService.
  Simplify MockVpn.
  Test a VPN with an underlying network that does not yet exist.