msc: Permit optional authentication before reject/timeout

Tests like TC_lu_imsi_reject, TC_lu_imsi_timeout_gsup and
TC_cmserv_imsi_unknown all expected a reject straight in response
to the LU REQ / CM SERV REQ.  However, the MSC may very well decide
to perform authentication beforehand.  It's an implementation
detail when a MSC/VLR performs authentication, so the tests should
be tolerant to this.

This primarily shows up in 3G/Iu/RANAP related tests, as authentication
is mandatory there.

Change-Id: Icdd3f34eca08092703ab2ba9a8e755e2d609a59b
diff --git a/msc/MSC_Tests.ttcn b/msc/MSC_Tests.ttcn
index 52aa685..e1e5088 100644
--- a/msc/MSC_Tests.ttcn
+++ b/msc/MSC_Tests.ttcn
@@ -583,6 +583,7 @@
 
 	f_create_gsup_expect(hex2str(g_pars.imsi));
 	f_cl3_or_initial_ue(l3_lu);
+	f_mm_auth();
 	GSUP.receive(tr_GSUP_UL_REQ(g_pars.imsi));
 	GSUP.send(ts_GSUP_UL_ERR(g_pars.imsi, 23));
 	alt {
@@ -612,6 +613,7 @@
 
 	f_create_gsup_expect(hex2str(g_pars.imsi));
 	f_cl3_or_initial_ue(l3_lu);
+	f_mm_auth();
 	GSUP.receive(tr_GSUP_UL_REQ(g_pars.imsi));
 	/* Normally the HLR would need to respond here, but we decide to force a timeout here */
 	alt {
@@ -678,6 +680,7 @@
 
 	/* Send BSSAP_Conn_Req with COMPL L3 INFO to MSC */
 	f_cl3_or_initial_ue(l3_info);
+	f_mm_auth();
 
 	timer T := 10.0;
 	T.start;