bsc: remove flush from f_expect_chan_rel

When we're expecting release, it can be non-deterministic / timing dependent to
flush the RSL queue. Particularly the RR Release message is typically already
in the queue when f_expect_chan_rel() is called and would be lost.

It turns out that none of the current callers need the flush feature.

If a test needs it, we can add a separate f_rsl_flush() function and call that,
no need to clutter up the f_expect_chan_rel() argument list. I had such
function but found that no caller needs it, so dropped it.

Related: OS#3413
Change-Id: Ie1be30c3f109dda8c58c523df508211f8e20aad3
diff --git a/bsc/BSC_Tests.ttcn b/bsc/BSC_Tests.ttcn
index e3ac707..551ffe0 100644
--- a/bsc/BSC_Tests.ttcn
+++ b/bsc/BSC_Tests.ttcn
@@ -824,14 +824,10 @@
 	setverdict(pass);
 }
 
-function f_expect_chan_rel(integer bts_nr, RslChannelNr rsl_chan_nr, boolean flush := true,
+function f_expect_chan_rel(integer bts_nr, RslChannelNr rsl_chan_nr,
 			   boolean handle_rll_rel := true) runs on test_CT {
 
 	var RslLinkId main_dcch := valueof(ts_RslLinkID_DCCH(0));
-	if (flush) {
-		/* Clear the queue, it might still contain stuff like IMMEDIATE ASSIGN */
-		IPA_RSL[bts_nr].clear;
-	}
 	alt {
 	/* ignore DEACTIVATE SACCH (if any) */
 	[] IPA_RSL[bts_nr].receive(tr_ASP_RSL_UD(IPAC_PROTO_RSL_TRX0,
@@ -912,7 +908,7 @@
 	/* release the SCCP connection */
 	BSSAP.send(ts_BSSAP_DISC_req(dt.sccp_conn_id, 0));
 
-	f_expect_chan_rel(0, dt.rsl_chan_nr, true, false);
+	f_expect_chan_rel(0, dt.rsl_chan_nr, handle_rll_rel := false);
 	setverdict(pass);
 }
 
@@ -934,7 +930,7 @@
 	[] BSSAP.receive(tr_BSSAP_DISC_ind(dt.sccp_conn_id, ?, ?)) { }
 	}
 
-	f_expect_chan_rel(0, dt.rsl_chan_nr, false);
+	f_expect_chan_rel(0, dt.rsl_chan_nr);
 	setverdict(pass);
 }