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
Test: binderRpcTest, binderRpcBenchmark
Change-Id: If07afd9af680cd2a5ece6506df5383e5cc258663
diff --git a/libs/binder/tests/IBinderRpcTest.aidl b/libs/binder/tests/IBinderRpcTest.aidl
index 814e094..ef4198d 100644
--- a/libs/binder/tests/IBinderRpcTest.aidl
+++ b/libs/binder/tests/IBinderRpcTest.aidl
@@ -18,7 +18,7 @@
     oneway void sendString(@utf8InCpp String str);
     @utf8InCpp String doubleString(@utf8InCpp String str);
 
-    // number of known RPC binders to process, RpcState::countBinders by connection
+    // number of known RPC binders to process, RpcState::countBinders by session
     int[] countBinders();
 
     // Caller sends server, callee pings caller's server and returns error code.
@@ -36,7 +36,7 @@
     // should always return the same binder
     IBinder alwaysGiveMeTheSameBinder();
 
-    // Idea is that the server will not hold onto the session, the remote connection
+    // Idea is that the server will not hold onto the session, the remote session
     // object must. This is to test lifetimes of binder objects, and consequently, also
     // identity (since by assigning sessions names, we can make sure a section always
     // references the session it was originally opened with).