Fix binstub test on windows.

sdk/lib/_internal/pub/test/global/binstubs/missing_script_test.dart

Index: sdk/lib/_internal/pub/test/global/binstubs/missing_script_test.dart
diff --git a/sdk/lib/_internal/pub/test/global/binstubs/missing_script_test.dart b/sdk/lib/_internal/pub/test/global/binstubs/missing_script_test.dart
index 084c0c7631fb72e9d7c6743ce37ae14791052034..190e56bd87b06268099984fc4269da242ccc30f1 100644
--- a/sdk/lib/_internal/pub/test/global/binstubs/missing_script_test.dart
+++ b/sdk/lib/_internal/pub/test/global/binstubs/missing_script_test.dart
@@ -2,9 +2,8 @@
 // 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_stream.dart';
+import 'package:path/path.dart' as p;
 
-import '../../../lib/src/exit_codes.dart' as exit_codes;
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 
@@ -25,8 +24,8 @@ main() {
 
     pub.stderr.expect('Warning: Executable "missing" runs '
         '"bin/not_here.dart", which was not found in foo.');
-    pub.stderr.expect('Warning: Executable "nope" runs "bin/nope.dart", which '
-        'was not found in foo.');
+    pub.stderr.expect('Warning: Executable "nope" runs '
+        '"${p.join('bin', 'nope.dart')}", which was not found in foo.');
     pub.shouldExit();
   });
 }