bscnat: Introduce test TC_ctrl_location

It checks location-state TRAP is forwaded correctly in BSC-NAT from BSC
towards locally connected CTRL client, with variable names updated to
contain BSC/BTS indexes.
It also verifies commands can be applied (SET) in inverse direction.

Change-Id: If28aba011a1903788cacbc10c0b62954925d4b1f
diff --git a/bsc-nat/BSC_MS_ConnectionHandler.ttcn b/bsc-nat/BSC_MS_ConnectionHandler.ttcn
index f7126fd..f011c39 100644
--- a/bsc-nat/BSC_MS_ConnectionHandler.ttcn
+++ b/bsc-nat/BSC_MS_ConnectionHandler.ttcn
@@ -210,4 +210,8 @@
 	}
 }
 
+function bsc_ms_do_nothing(charstring id)
+runs on BSC_MS_ConnHdlr {
+}
+
 }