Fix warnings_checker.dart handling of multitests

tests/language_strong/constructor_duplicate_final_test.dart

 // Copyright (c) 2014, 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.
 
 // Check that duplicate initialization of a final field is a runtime error.
 
 
 class Class {
   final f = 10;
 
-  Class(v) : f = v; // /// 01: runtime error, static type warning
+  Class(v) : f = v; // //# 01: runtime error, static type warning
 
-  Class(this.f); // /// 02: runtime error, static type warning
+  Class(this.f); // //# 02: runtime error, static type warning
 
   // If a field is initialized multiple times in the initializer
   // list, it's a compile time error.
-  Class(this.f) : f = 0; // /// 03: compile-time error
+  Class(this.f) : f = 0; // //# 03: compile-time error
 }
 
 main() {
-  new Class(5); // /// 01: continued
-  new Class(5); // /// 02: continued
-  new Class(5); // /// 03: continued
+  new Class(5); // //# 01: continued
+  new Class(5); // //# 02: continued
+  new Class(5); // //# 03: continued
 }