pcu: SNS: TC_sns_so_bvc_reset_unknown_bvci: use g_handle_rx_alive

The g_handle_rx_alive allows ignoring any ALIVE PDUs when
using f_exp_ns().
This improves the stability as the ALIVE and BVC-RESET
can come in any order.

Change-Id: I3b4ab4093b3e5bee7e32fdf6c1de3f692b13a35f
diff --git a/pcu/PCU_Tests_SNS.ttcn b/pcu/PCU_Tests_SNS.ttcn
index 20ab608..b6a1790 100644
--- a/pcu/PCU_Tests_SNS.ttcn
+++ b/pcu/PCU_Tests_SNS.ttcn
@@ -267,16 +267,13 @@
  * PCU  -> SGSN: BVCI 24 BSSGP-STATUS Unknown BVCI
  */
 testcase TC_sns_so_bvc_reset_unknown_bvci() runs on RAW_Test_CT {
+	g_handle_rx_alive := true;
 	f_init_ns_codec(mp_nsconfig);
 	f_init_pcuif();
 	f_incoming_sns_size();
 	f_incoming_sns_config();
 	f_outgoing_sns_config();
 
-	/* wait for one ALIVE cycle, then ACK any further ALIVE in the background */
-	as_rx_alive_tx_ack(oneshot := true);
-	activate(as_rx_alive_tx_ack());
-
 	/* Expect BVC-RESET, but ignore it to prevent a race condition of BVC RESETs */
 	var template PDU_NS pdu := tr_NS_UNITDATA(t_SduCtrlB, 0, decmatch tr_BVC_RESET(?, 0, omit));
 	f_ns_exp(pdu, idx := 0);