pcu: Introduce as_ms_rx_ignore_empty helper

It will be further used in follow-up patches.

Change-Id: I3c80ba4b8d229fa4a75dfd04abb7c5aae26e221c
diff --git a/pcu/PCU_Tests.ttcn b/pcu/PCU_Tests.ttcn
index 2cc6fad..c347761 100644
--- a/pcu/PCU_Tests.ttcn
+++ b/pcu/PCU_Tests.ttcn
@@ -1984,19 +1984,9 @@
 					  block_nr := nr.blk_nr));
 		repeat;
 	}
-	[mp_osmo_pcu_newer_than_0_9_0 and N3105 == N3105_MAX]
-		BTS.receive(tr_PCUIF_DATA_PDTCH(nr.bts_nr,
-						tr_PCUIF_DATA(nr.trx_nr, nr.ts_nr, sapi := PCU_IF_SAPI_PDTCH),
-						omit)) -> value data_msg {
-		/* We may already receive idle blocks before our own TTCN3 timer
-		 * triggers due to the TBF being released. Keep going until our T_3195 triggers. */
-		nr := ts_TsTrxBtsNum;
-		BTS.send(ts_PCUIF_RTS_REQ(nr.bts_nr, nr.trx_nr, nr.ts_nr,
-					  sapi := PCU_IF_SAPI_PDTCH, fn := 0,
-					  arfcn := f_trxnr2arfcn(valueof(nr.trx_nr)),
-					  block_nr := nr.blk_nr));
-		repeat;
-	}
+	/* We may already receive idle blocks before our own TTCN3 timer
+	 * triggers due to the TBF being released. Keep going until our T_3195 triggers. */
+	[mp_osmo_pcu_newer_than_0_9_0 and N3105 == N3105_MAX] as_pcuif_rx_ignore_empty(nr);
 	[T_3195.running] T_3195.timeout {
 		log("T_3195 timeout");
 		/* Done in alt, wait for pending RTS initiated previously in