Fix warnings_checker.dart handling of multitests

tests/language/super_no_such_method1_test.dart

 // Copyright (c) 2016, 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 {
   noSuchMethod(im) => 42;
 }
 
 class B extends A {
   noSuchMethod(im) => 87;
 
-  foo() => super.foo(); /// 01: static type warning
+  foo() => super.foo(); //# 01: static type warning
 }
 
 main() {
-  Expect.equals(42, new B().foo()); /// 01: continued
+  Expect.equals(42, new B().foo()); //# 01: continued
 }