The downstream do not be tracked if PrivateAddressCoordinator just
return cached address. Then, PrivateAddressCoordinator would not notify
that downstream if conflict happen.
Also remove the null check in getDownstreamPrefix because:
- An IpServer is only added to mDownstreams by requestDownstreamAddress.
- That method will only add the IpServer to mDownstreams if it has an
IPv4 address.
- As soon as that method returns, the IpServer sets mIpv4Address to the
address that was returned.
- When an IpServer is torn down, mIpv4Address is set to null after
releaseDownstream is called.
So it should never be possible for this to return null.
Bug: 168169687
Test: atest CtsTetheringTest
atest TetheringTests
Change-Id: Ide5206b013acdc499344e1c839a830c5b245af41
634f0a8ec1