Testing AIDL delegator class with RPC

Similar set up to what will be in Auto. Trying to find an easy way to
set up the shim without so much manual boilerplating.

A shim process gets the binder from a RPC connection and uses that as
the implementation for a local registered service.

Test: atest binderRpcTest

Change-Id: Ia4fc4cad6c7bc90f82a768bcf1d17d98cb321a08