MSC_Tests: Reply to Classmark Req in TC_lu_imsi_auth_tmsi_encr_3_1_no_cm

After osmo-msc I73c7cb6a86624695bd9c0f59abb72e2fdc655131, osmo-msc
sends a BSSMAP Classmark Request if encounters a missing Classmark,
which is the case during LU when A5/3 is enabled.

Fix this test by answering the Classmark Request, if any.

Change-Id: I25578c050b7e105ed71b064891d4cd418ee30fcf

library/BSSMAP_Templates.ttcn

@@ -885,6 +885,17 @@ template PDU_BSSAP tr_BSSMAP_CipherModeRej modifies tr_BSSAP_BSSMAP := {
 	}
 }
 
+template PDU_BSSAP tr_BSSMAP_ClassmarkReq modifies tr_BSSAP_BSSMAP := {
+	pdu := {
+		bssmap := {
+			classmarkRequest := {
+				messageType := '58'O,
+				talkerPriority := *
+			}
+		}
+	}
+}
+
 template BSSMAP_IE_ClassmarkInformationType2 ts_CM2_default := {
 	elementIdentifier := '12'O,
 	lengthIndicator := 0,	/* overwritten */

msc/MSC_Tests.ttcn

@@ -1602,6 +1602,10 @@ private function f_tc_lu_imsi_auth_tmsi_encr_3_1(charstring id, BSC_ConnHdlrPars
 	}
 	f_mm_auth();
 	alt {
+	[] BSSAP.receive(tr_BSSMAP_ClassmarkReq) {
+		BSSAP.send(ts_BSSMAP_ClassmarkUpd(g_pars.cm2, g_pars.cm3));
+		repeat;
+		}
 	[] BSSAP.receive(tr_PDU_DTAP_MT(tr_ML3_MT_LU_Rej)) {
 		f_expect_clear();
 		}