libbinder: RPC big 'session' rename

Before, 'connection' was used for a group of TCP connection. This
updates the names for most types to work with the following definitions:

- session - group of connections
- connection - a single tcp connection
- socket - only when referring to a socket being setup for a connection

Bug: N/A
Fixes: 187393805 # conflict
Test: binderRpcTest, binderRpcBenchmark
Change-Id: If07afd9af680cd2a5ece6506df5383e5cc258663
(cherry picked from commit bdb53ab39d08f9d189706532d347f575cbdac257)
diff --git a/libs/binder/Android.bp b/libs/binder/Android.bp
index a97cf87..be260e8 100644
--- a/libs/binder/Android.bp
+++ b/libs/binder/Android.bp
@@ -112,7 +112,7 @@
         "PersistableBundle.cpp",
         "ProcessState.cpp",
         "RpcAddress.cpp",
-        "RpcConnection.cpp",
+        "RpcSession.cpp",
         "RpcServer.cpp",
         "RpcState.cpp",
         "Static.cpp",