Get binstubs working on Windows.

sdk/lib/_internal/pub/test/global/binstubs/no_executables_flag_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.
 
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
+import 'utils.dart';
 
 main() {
   initConfig();
   integration("does not create binstubs if --no-executables is passed", () {
     d.dir("foo", [
       d.pubspec({
         "name": "foo",
         "executables": {
           "one": null
         }
       }),
       d.dir("bin", [
         d.file("one.dart", "main() => print('ok');")
       ])
     ]).create();
 
     schedulePub(args: ["global", "activate", "--source", "path", "../foo"]);
 
     schedulePub(args: [
       "global", "activate", "--source", "path", "../foo", "--no-executables"
     ]);
 
     // Should still delete old one.
     d.dir(cachePath, [
       d.dir("bin", [
-        d.nothing("one")
+        d.nothing(binStubName("one"))
       ])
     ]).validate();
   });
 }