Fix warnings_checker.dart handling of multitests

tests/language/field_type_check2_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.
 
 class A {
   A a;
 
   bar(c) {
-    c.a = 2; /// 01: dynamic type error
+    c.a = 2; //# 01: dynamic type error
   }
 }
 
 class B {
   int a;
 }
 
 main() {
-  new A().bar(new A()); /// 01: continued
+  new A().bar(new A()); //# 01: continued
   new A().bar(new B());
 }