msc: fix race condition in TC_mm_id_resp_no_identity

This testcase is failing sporadically ever since it was introduced
back in 2019, during 36C3.  The problem is that osmo-msc does not
react to the malformed MM IDENTITY RESPONSE immediately, but only
after timeout of timer X1 (5 seconds, by default);  while the
testsuite expects the LU REJECT to be received within 5 seconds.

We should ideally fix osmo-msc to react immediately, but for now
let's enlarge the LU REJECT waiting timeout in the testcase.

Change-Id: I5d2b5d49df8f7ae1eb12fc137f4256fe6fab9117
Related: OS#6426, OS#4340
diff --git a/msc/BSC_ConnectionHandler.ttcn b/msc/BSC_ConnectionHandler.ttcn
index be12fae..6f8078b 100644
--- a/msc/BSC_ConnectionHandler.ttcn
+++ b/msc/BSC_ConnectionHandler.ttcn
@@ -916,11 +916,11 @@
 	}
 }
 
-function f_expect_lu_reject(template OCT1 cause := ?) runs on BSC_ConnHdlr {
+function f_expect_lu_reject(template OCT1 cause := ?, float Tval := 5.0) runs on BSC_ConnHdlr {
 	var PDU_DTAP_MT dtap_mt;
-	timer T := 5.0;
+	timer T;
 
-	T.start;
+	T.start(Tval);
 	alt {
 	[] BSSAP.receive(tr_PDU_DTAP_MT(tr_ML3_MT_LU_Rej(cause))) {
 		setverdict(pass);