Fix warnings_checker.dart handling of multitests

tests/language/redirecting_factory_default_values_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.
 
 // Test that parameter default values are disallowed in a redirecting factory.
 
 import "package:expect/expect.dart";
 
 class A {
   A(this.a, [this.b = 0]);
   factory A.f(a) = A;
-  factory A.g(a, [b = 0]) = A; // /// 01: compile-time error
-  factory A.h(a, {b: 0}) = A; // /// 02: compile-time error
+  factory A.g(a, [b = 0]) = A; // //# 01: compile-time error
+  factory A.h(a, {b: 0}) = A; // //# 02: compile-time error
 
  int a;
  int b;
 }
 
 main() {
   var x = new A.f(42);
   Expect.equals(x.a, 42);
   Expect.equals(x.b, 0);
 
   var y = new A.f(42, 43);
   Expect.equals(y.a, 42);
   Expect.equals(y.b, 43);
 }