Get binstubs working on Windows.

sdk/lib/_internal/pub_generated/test/global/binstubs/binstub_runs_precompiled_snapshot_test.dart

 import 'package:scheduled_test/scheduled_test.dart';
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
+import 'utils.dart';
 main() {
   initConfig();
   integration("the binstubs runs a precompiled snapshot if present", () {
     servePackages((builder) {
       builder.serve("foo", "1.0.0", pubspec: {
         "executables": {
           "foo-script": "script"
         }
       },
           contents: [
               d.dir("bin", [d.file("script.dart", "main(args) => print('ok');")])]);
     });
     schedulePub(args: ["global", "activate", "foo"]);
     d.dir(
         cachePath,
         [
             d.dir(
                 "bin",
-                [d.matcherFile("foo-script", contains("script.dart.snapshot"))])]).validate();
+                [
+                    d.matcherFile(
+                        binStubName("foo-script"),
+                        contains("script.dart.snapshot"))])]).validate();
   });
 }