BTS_Tests: fix "Timeout waiting for L1CTL_FBSB_CONF"

Since [1] was merged, sending the L1CTL_DM_REL_REQ message alone
is not enough to be able to tune back to BCCH.  We also need to
send L1CTL_RESET_REQ, so the trxcon's state is reset properly.

This patch fixes the following testcases:

* TC_sacch_chan_act_ho_async,
* TC_sacch_chan_act_ho_sync,
* TC_conn_fail_crit.

Change-Id: I07192e8a3127f8d9557a4b8aac3ca002f511a1d5
Related: [1] I5bbe6ca4cc6299f9faf343822c992a6872a45081 (osmocom-bb.git)
diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index 9baee40..25e7952 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -1506,6 +1506,7 @@
 
 	f_rsl_chan_deact();
 	f_L1CTL_DM_REL_REQ(L1CTL, g_chan_nr);
+	f_L1CTL_RESET(L1CTL);
 
 	/* Tune back to CCCH/BCCH */
 	f_l1_tune(L1CTL);
@@ -1586,6 +1587,7 @@
 
 	f_rsl_chan_deact();
 	f_L1CTL_DM_REL_REQ(L1CTL, g_chan_nr);
+	f_L1CTL_RESET(L1CTL);
 
 	/* Tune back to CCCH/BCCH */
 	f_l1_tune(L1CTL);
@@ -1614,6 +1616,7 @@
 
 	f_rsl_chan_deact();
 	f_L1CTL_DM_REL_REQ(L1CTL, g_chan_nr);
+	f_L1CTL_RESET(L1CTL);
 
 	/* Tune back to CCCH/BCCH */
 	f_l1_tune(L1CTL);
@@ -1641,6 +1644,7 @@
 
 	f_rsl_chan_deact();
 	f_L1CTL_DM_REL_REQ(L1CTL, g_chan_nr);
+	f_L1CTL_RESET(L1CTL);
 
 	/* Tune back to CCCH/BCCH */
 	f_l1_tune(L1CTL);
@@ -3944,7 +3948,8 @@
 
 	f_est_dchan();
 	f_sleep(2.0);
-	L1CTL.send(ts_L1CTL_DM_REL_REQ(g_chan_nr));
+	f_L1CTL_DM_REL_REQ(L1CTL, g_chan_nr);
+	f_L1CTL_RESET(L1CTL);
 	f_l1_tune(L1CTL); /* tune back to BCCH */
 
 	timer T := 40.0;