BSC_Tests: fix early mtc.stop in TC_chan_rel_rr_cause()

Calling f_shutdown_helper() in f_tc_chan_rel_rr_cause() leads to
premature test case termination, so only one out of 6 cause values
gets checked.  Move it to TC_chan_rel_rr_cause().

Change-Id: Ic7df15b496fc0750e4f694b1ae79398216f498a7
diff --git a/bsc/BSC_Tests.ttcn b/bsc/BSC_Tests.ttcn
index 175b820..87a15ea 100644
--- a/bsc/BSC_Tests.ttcn
+++ b/bsc/BSC_Tests.ttcn
@@ -1947,7 +1947,6 @@
 	}
 
 	f_expect_chan_rel(0, dt.rsl_chan_nr, expect_rll_rel_req := false, expect_rr_cause := expect_rr_cause);
-	f_shutdown_helper();
 }
 
 /* Test that Clear Command cause codes affect the RR Channel Release cause code */
@@ -1960,6 +1959,8 @@
 	f_tc_chan_rel_rr_cause(GSM0808_CAUSE_RADIO_INTERFACE_MESSAGE_FAILURE, GSM48_RR_CAUSE_PROT_ERROR_UNSPC);
 	f_tc_chan_rel_rr_cause(GSM0808_CAUSE_RADIO_INTERFACE_FAILURE, GSM48_RR_CAUSE_ABNORMAL_UNSPEC);
 	f_tc_chan_rel_rr_cause(GSM0808_CAUSE_EQUIPMENT_FAILURE, GSM48_RR_CAUSE_ABNORMAL_UNSPEC);
+
+	f_shutdown_helper();
 }
 
 /* Test behavior if RSL EST IND for non-active channel */