Fix warnings_checker.dart handling of multitests

tests/language/mixin_super_bound2_test.dart

 // Copyright (c) 2015, 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.
 // SharedOptions=--supermixin
 
 import "package:expect/expect.dart";
 
 bool inCheckedMode() {
   try {
     var i = 42;
     String s = i;
   } on TypeError catch (e) {
     return true;
   }
   return false;
 }
 
 class MS<U, V
-    extends U /// 01: static type warning
+    extends U //# 01: static type warning
     > { }
 
 class M<U
-    extends V /// 01: continued
+    extends V //# 01: continued
     , V> extends MS<V, U> { }
 
 class NS<U
-    extends V /// 01: continued
+    extends V //# 01: continued
     , V> { }
 
 class N<U, V
-    extends U /// 01: continued
+    extends U //# 01: continued
     > extends NS<V, U> { }
 
 class S<T> { }
 
 class MNA<U, V, W> extends S<List<U>>
     with M<List<V>, List<U>>, N<List<W>, List<W>> { }
 
 class MNA2<U, V, W> = S<List<U>>
     with M<List<W>, List<W>>, N<List<U>, List<V>>;
 
 class MNA3<U, V, W> extends S<List<U>>
     with MNA<U, V, W>, MNA2<List<U>, List<V>, List<W>> { }
 
 class MNA4<U, V, W> = S<List<U>>
     with MNA<U, V, W>, MNA2<List<U>, List<V>, List<W>>;
 
 main() {
   new MNA<num, int, bool>();
   new MNA2<num, int, bool>();
   new MNA3<num, int, bool>();
   new MNA4<num, int, bool>();
   bool shouldThrow = false
-      || inCheckedMode() /// 01: continued
+      || inCheckedMode() //# 01: continued
       ;
   if (shouldThrow) {
     // Type parameter U of M must extend type parameter V, but
     // type argument List<num> is not a subtype of List<int>.
     Expect.throws(() => new MNA<int, num, bool>(), (e) => e is TypeError);
     // Type parameter V of N must extend type parameter U, but
     // type argument List<num> is not a subtype of List<int>.
     Expect.throws(() => new MNA2<int, num, bool>(), (e) => e is TypeError);
     // Type parameter V of N must extend type parameter U, but
     // type argument List<List<num>> is not a subtype of List<List<int>>.
     Expect.throws(() => new MNA3<int, num, bool>(), (e) => e is TypeError);
     // Type parameter V of N must extend type parameter U, but
     // type argument List<List<num>> is not a subtype of List<List<int>>.
     Expect.throws(() => new MNA4<int, num, bool>(), (e) => e is TypeError);
   } else {
     new MNA<int, num, bool>();
     new MNA2<int, num, bool>();
     new MNA3<int, num, bool>();
     new MNA4<int, num, bool>();
   }
 }