Fix warnings_checker.dart handling of multitests

tests/language/malbounded_redirecting_factory2_test.dart

 // Copyright (c) 2013, 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.
 
 import 'package:expect/expect.dart';
 
 class A<Ta
-           extends num // /// 02: continued
+           extends num // //# 02: continued
                       > implements B<Ta>, C<Ta> { }
 
 class B<Tb
-           extends num // /// 03: continued
+           extends num // //# 03: continued
                       > {
   factory B() = A<Tb>;
 }
 
 class C<Tc
-           extends num // /// 04: continued
+           extends num // //# 04: continued
                       > {
   factory C() = B<Tc>;
 }
 
 class D<Td> {
   test() => new C<Td>();
 }
 
 main() {
   new D<int>().test();
-  new D<String>().test(); // /// 01: static type warning
-  new D<String>().test(); // /// 02: static type warning, dynamic type error
-  new D<String>().test(); // /// 03: static type warning, dynamic type error
-  new D<String>().test(); // /// 04: static type warning, dynamic type error
+  new D<String>().test(); // //# 01: static type warning
+  new D<String>().test(); // //# 02: static type warning, dynamic type error
+  new D<String>().test(); // //# 03: static type warning, dynamic type error
+  new D<String>().test(); // //# 04: static type warning, dynamic type error
 }