DIAMETER_Emulation: Support forwarding messages identified by ete_id to a client component

This is useful in the scenarios where the client component submits a
IMSI-based transaction such as AIR, but its answer (AIA) contains no
IMSI (as per what's specified in TS 29.272 5.2.3.1). As a result, the
received AIA message would be enqueued in the DIAMETER_UNIT.

With this new feature, the test can create an expect using the
End-to-End Identifier of the message it is going to transmit, and
receive the answer in the same DIAMETER_CLIENT port the request was
transmitted, even if it contains no IMSI.

Related: OS#5757
Change-Id: I25e44146d2c49e308c1fb490b499e70ac6045f2f
diff --git a/mme/MME_Tests.ttcn b/mme/MME_Tests.ttcn
index 17a4d60..cc75377 100644
--- a/mme/MME_Tests.ttcn
+++ b/mme/MME_Tests.ttcn
@@ -361,7 +361,7 @@
 	g_Tguard.start(t_guard);
 	activate(as_Tguard());
 	if (DIAMETER_PROC.checkstate("Connected")) {
-		f_diameter_expect(g_pars.ue_pars.imsi);
+		f_diameter_expect_imsi(g_pars.ue_pars.imsi);
 	}
 	if (SGsAP_PROC.checkstate("Connected")) {
 		/* Route all SGsAP mesages for our IMSIto us */