bts: Check if BTS_TRXC port is mapped before attempting UDP socket connect

A large number of our tests is currently failing with
	BTS_Tests.ttcn:341 Dynamic test case error: IPL4 Test Port not mapped
which was introduced by Change-Id Ie7d311bf8f03bf9b1d29b5bb28ffad793f215fd1

Change-Id: Ia1ef4ac7dcfec137a8613bc49a7f312d81a86153
diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index e10d967..9371612 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -505,7 +505,7 @@
 	map(self:L1CTL, system:L1CTL);
 	f_connect_reset(L1CTL);
 
-	if (mp_bts_trxc_port != -1) {
+	if (mp_bts_trxc_port != -1 and BTS_TRXC.checkstate("Mapped")) {
 		f_init_trxc(BTS_TRXC, id, g_bts_trxc_conn_id);
 	}