Allow bypassing private DNS via bindProcessToNetwork.

Currently, bypassing private DNS requires calling the deprecated
setProcessDefaultNetworkForHostResolution. Allow apps to do this
via the non-deprecated binProcessForNetwork as well.

This has fewer backwards compatibility concerns than the
alternative approach of having setProcessDefaultNetwork call
setProcessDefaultNetworkForHostResolution. That approach would
have been problematic, for example, if an app did:

  cm.bindProcessToNetwork(network);
  ...
  cm.bindProcessToNetwork(null);

In this case, it would be difficult to know whether to clear the
resolver mapping as well: what if an app had also called
setProcessDefaultNetworkForHostResolution?

Similarly, it would be difficult to know what to do if an app did:

  cm.setProcessDefaultNetworkForHostResolution(network);
  cm.bindProcessToNetwork(null);

This approach does not have these concerns, and has no effect
on apps that don't call Network.getPrivateDnsBypassingCopy, which
regular apps don't have permission to use. It also provides a
path to deprecate setProcessDefaultNetworkForHostResolution.

Bug: 112869080
Test: atest android.net.cts.ConnectivityManagerTest android.net.cts.MultinetworkApiTest
Change-Id: I4158a37b6ed87a9a9b2677c526dcfee8af48e483