mgw: Introduce test TC_crcx_osmux_257

Related: SYS#5987
Change-Id: I74e6c760e076fe2547b6297a54524255fb8b
diff --git a/mgw/expected-results.xml b/mgw/expected-results.xml
index 8b17fb1..577b6e3 100644
--- a/mgw/expected-results.xml
+++ b/mgw/expected-results.xml
@@ -29,6 +29,7 @@
   <testcase classname='MGCP_Test' name='TC_crcx_osmux_wildcard' time='MASKED'/>
   <testcase classname='MGCP_Test' name='TC_crcx_osmux_fixed' time='MASKED'/>
   <testcase classname='MGCP_Test' name='TC_crcx_osmux_fixed_twice' time='MASKED'/>
+  <testcase classname='MGCP_Test' name='TC_crcx_osmux_257' time='MASKED'/>
   <testcase classname='MGCP_Test' name='TC_one_crcx_receive_only_osmux' time='MASKED'/>
   <testcase classname='MGCP_Test' name='TC_one_crcx_loopback_osmux' time='MASKED'/>
   <testcase classname='MGCP_Test' name='TC_two_crcx_and_rtp_osmux' time='MASKED'/>