BTS_Tests: print DL TCH length in f_TC_speech_osmux()

I forgot to update this function in [1].

Change-Id: I2a2dccd32aaf94afc31bd44f14fdc1cfdf554d2d
Related: [1] I5848bd8acd220c1c4d2db01b71bb57e785dc9de7
diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index b8c4118..7691187 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -8439,9 +8439,9 @@
 	Td.start(2.0);
 	alt {
 	[] L1CTL.receive(tr_L1CTL_TRAFFIC_IND(g_chan_nr, frame := exp_rtp_pl)) -> value l1_dl {
-		log("TCH received: ", l1_dl.payload.traffic_ind.data);
-		L1CTL.send(ts_L1CTL_TRAFFIC_REQ(g_chan_nr, l1_dl.dl_info.link_id,
-			   l1_dl.payload.traffic_ind.data));
+		var octetstring data := l1_dl.payload.traffic_ind.data;
+		log("TCH received (len=", lengthof(data), "): ", data);
+		L1CTL.send(ts_L1CTL_TRAFFIC_REQ(g_chan_nr, l1_dl.dl_info.link_id, data));
 		setverdict(pass);
 		}
 	[] L1CTL.receive(tr_L1CTL_TRAFFIC_IND(g_chan_nr, frame := ?)) -> value l1_dl {