add three tests for CIPHER MODE COMPLETE without algo

Add three tests which exercise MSC behaviour when a CIPHER MODE
COMPLETE command lacks the optional chosenEncryptionAlgorithm IE.
Check for behaviour with A5/1, A5/3, and A5/1 + A5/3 configured
in the network, and expect the location update to succeed.

These tests pass on master, but they should somehow verify the
cipher the MSC ends up using. I am not quite sure how to do that.
Would inspecting the MSC's VTY be a reasonable approach? How
could his be done by code which runs on BSC_ConnectionHandler?

Change-Id: I1a2a126795c544613a7a87e238e1fc8c4e943885
Related: OS#2872
diff --git a/msc/BSC_ConnectionHandler.ttcn b/msc/BSC_ConnectionHandler.ttcn
index 93a311e..796b0ce 100644
--- a/msc/BSC_ConnectionHandler.ttcn
+++ b/msc/BSC_ConnectionHandler.ttcn
@@ -494,12 +494,25 @@
 	}
 
 	f_mm_common();
+	f_msc_lu_hlr();
+	f_accept_reject_lu();
+	/* FIXME: there could be pending SMS or other common procedures by the MSC, let's ignore them */
+	f_expect_clear();
 
+	setverdict(pass);
+}
+
+function f_msc_lu_hlr() runs on BSC_ConnHdlr
+{
 	/* Expect MSC to perform LU with HLR */
 	GSUP.receive(tr_GSUP_UL_REQ(g_pars.imsi));
 	GSUP.send(ts_GSUP_ISD_REQ(g_pars.imsi, g_pars.msisdn));
 	GSUP.receive(tr_GSUP_ISD_RES(g_pars.imsi));
 	GSUP.send(ts_GSUP_UL_RES(g_pars.imsi));
+}
+
+function f_accept_reject_lu() runs on BSC_ConnHdlr {
+	var PDU_DTAP_MT dtap_mt;
 
 	alt {
 	[] BSSAP.receive(tr_PDU_DTAP_MT(tr_ML3_MT_LU_Acc)) -> value dtap_mt {
@@ -529,9 +542,6 @@
 
 	/* Wait for MM-Information (if enabled) */
 	f_expect_mm_info();
-
-	/* FIXME: there could be pending SMS or other common procedures by the MSC, let's ignore them */
-	f_expect_clear();
 	setverdict(pass);
 }