Fix warnings_checker.dart handling of multitests

tests/language/issue1363_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 // VMOptions=--enable_type_checks
 
 library Issue1363Test.dart;
 import 'issue1363_lib.dart' as lib;
 
 main() {
   new C().test();
 }
 
 class C {
   lib.Cup<lib.C> libCup;
   lib.Cup<C> myCup;
 
   C();
 
   test() {
     myCup = new lib.Cup<C>(new C());
     libCup = new lib.Cup<lib.C>(new lib.C());
 
     C contents = myCup.getContents(); // expect no warning or error
     bool hasThrown = false;
     try {
-      contents = libCup.getContents(); /// static type warning
+      contents = libCup.getContents(); //# static type warning
     } on TypeError catch (e) {
       hasThrown = true;
     }
   }
 }