bsc: add MSC pooling tests

The MSC pooling feature is implemented in osmo-bsc
Ifbdea197b26e88751a391c8a80c41f04e7d5e047.

A VTY command ('mscpool roundrobin next') that allows deterministic testing is
added in I2155d906505a26744966f442ffb1e87a6a9b494c.

osmo-bsc.cfg changes needed for these tests to succeed are in docker-playground
I1986e4ef43beee161c82193694421b56136c1afe

The new tests will fail until the above have been merged.

Change-Id: I21cbab193cd0de2e5692665442eae113d5f61904
diff --git a/bsc/MSC_ConnectionHandler.ttcn b/bsc/MSC_ConnectionHandler.ttcn
index feedc6f..fece825 100644
--- a/bsc/MSC_ConnectionHandler.ttcn
+++ b/bsc/MSC_ConnectionHandler.ttcn
@@ -482,7 +482,7 @@
 }
 
 /* register an expect with the BSSMAP core */
-private function f_create_bssmap_exp(octetstring l3_enc) runs on MSC_ConnHdlr {
+function f_create_bssmap_exp(octetstring l3_enc) runs on MSC_ConnHdlr {
 	RAN.call(RAN_register:{l3_enc, self}) {
 		[] RAN.getreply(RAN_register:{?, ?}) {};
 	}
@@ -515,7 +515,11 @@
 }
 
 type record TestHdlrParamsMSCPool {
-	integer bssap_idx
+	integer bssap_idx,
+	SCCP_PAR_Address sccp_addr_msc optional,
+	SCCP_PAR_Address sccp_addr_bsc optional,
+	integer rsl_idx,
+	PDU_ML3_MS_NW l3_info optional
 }
 
 type record TestHdlrParams {
@@ -563,7 +567,11 @@
 	aoip := true,
 	use_osmux := false,
 	mscpool := {
-		bssap_idx := 0
+		bssap_idx := 0,
+		sccp_addr_msc := omit,
+		sccp_addr_bsc := omit,
+		rsl_idx := 0,
+		l3_info := omit
 	}
 }