libbinder: RPC with getInterfaceDescriptor

I need to follow up/add tests for all the built-in transactions, since
they need to call markForBinder, but this is required for making RPC
calls over NDK because this backend proactively retrieves the interface
descriptor (side note: potential optimization improvement).

Bug: 167966510
Test: binderRpcTest
Change-Id: I62ec7bf09040563d46aa43a685efb87e3add524f