fix MGCP_Test.TC_one_crcx_loopback_rtp_implicit expectations

osmo-mgw should not respond to unknown peers. The test expected the
wrong thing, because of an old hack for 3G voice. Fix that.

Related: OS#6424
Change-Id: Ibe2ee59d1ed2c25ffef7e8534c172ac190b4983d
diff --git a/mgw/MGCP_Test.ttcn b/mgw/MGCP_Test.ttcn
index 3161079..7090b34 100644
--- a/mgw/MGCP_Test.ttcn
+++ b/mgw/MGCP_Test.ttcn
@@ -1931,11 +1931,22 @@
 
 		stats := f_rtpem_stats_get(RTPEM[0]);
 
-		if (stats.num_pkts_tx != stats.num_pkts_rx) {
-			setverdict(fail);
-		}
-		if (stats.bytes_payload_tx != stats.bytes_payload_rx) {
-			setverdict(fail);
+		if (one_phase) {
+			/* osmo-mgw knows both local and remote RTP address. Expect all packets to be reflected. */
+			if (stats.num_pkts_tx != stats.num_pkts_rx) {
+				setverdict(fail);
+			}
+			if (stats.bytes_payload_tx != stats.bytes_payload_rx) {
+				setverdict(fail);
+			}
+		} else {
+			/* osmo-mgw knows only the local RTP address. Expect no packets to be reflected. */
+			if (stats.num_pkts_rx > 0) {
+				setverdict(fail, "stats.num_pkts_rx=", stats.num_pkts_rx, ": osmo-mgw should not send RTP packets to an arbitrary peer");
+			}
+			if (stats.bytes_payload_rx > 0) {
+				setverdict(fail);
+			}
 		}
 
 		f_rtpem_stats_err_check(stats);