BSC_Tests.ttcn: introduce TC_chan_deact_silence

The idea of this test case is to verify channel deactivation
procedure due to no response to Immediate Assignment.

Change-Id: I00b0838c9f919303aef72280248b0d1317f42b3b
Related: OS#3709
diff --git a/bsc/expected-results.xml b/bsc/expected-results.xml
index d558e72..fd26922 100644
--- a/bsc/expected-results.xml
+++ b/bsc/expected-results.xml
@@ -10,6 +10,7 @@
   <testcase classname='BSC_Tests' name='TC_chan_act_ack_est_ind_refused' time='MASKED'/>
   <testcase classname='BSC_Tests' name='TC_chan_act_nack' time='MASKED'/>
   <testcase classname='BSC_Tests' name='TC_chan_exhaustion' time='MASKED'/>
+  <testcase classname='BSC_Tests' name='TC_chan_deact_silence' time='MASKED'/>
   <testcase classname='BSC_Tests' name='TC_chan_rel_rll_rel_ind' time='MASKED'/>
   <testcase classname='BSC_Tests' name='TC_chan_rel_conn_fail' time='MASKED'/>
   <testcase classname='BSC_Tests' name='TC_chan_rel_hard_clear' time='MASKED'/>