libbinder: use socket operations in testSupportVsockLoopback

Rewrites testSupportVsockLoopback to use socket operations
directly instead of the Rpc* classes so that the test also
works in single-threaded environments.

Bug: 224644083
Test: atest binderRpcTest
Change-Id: Ic30b5d91f72fb961b88ec4f9ba467daaf8c0a24a
1 file changed