Stop testcase execution after failing

This hopefully prevents the verdict from changing to a dynamic test case
error during an unclean termination

Change-Id: I20e156982ae8150a9e7a145f66283de4a5d8e0bd

bts/BTS_Tests.ttcn

@@ -757,7 +757,7 @@ private function f_sacch_missing(template octetstring l3_exp) runs on ConnHdlr {
 		var octetstring l3 := substr(dl.payload.data_ind.payload, 4, 19);
 		if (match(l3, l3_exp)) {
 			setverdict(fail, "Received unexpected SACCH ", dl);
-			self.stop;
+			mtc.stop;
 		} else {
 			repeat;
 		}