Store the async-await compiled pub code directly in the repo.

sdk/lib/_internal/pub_generated/test/run/nonexistent_script_test.dart

Index: sdk/lib/_internal/pub_generated/test/run/nonexistent_script_test.dart
diff --git a/sdk/lib/_internal/pub/test/run/nonexistent_script_test.dart b/sdk/lib/_internal/pub_generated/test/run/nonexistent_script_test.dart
similarity index 58%
copy from sdk/lib/_internal/pub/test/run/nonexistent_script_test.dart
copy to sdk/lib/_internal/pub_generated/test/run/nonexistent_script_test.dart
index ce385fc0dd9b66a487aa906055b836674412473c..6fd783e6a7569fb192a5ede3d13ffc29fdb1c9b8 100644
--- a/sdk/lib/_internal/pub/test/run/nonexistent_script_test.dart
+++ b/sdk/lib/_internal/pub_generated/test/run/nonexistent_script_test.dart
@@ -1,20 +1,11 @@
-// 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:path/path.dart' as p;
-
 import '../../lib/src/exit_codes.dart' as exit_codes;
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
-
 main() {
   initConfig();
   integration('Errors if the script does not exist.', () {
-    d.dir(appPath, [
-      d.appPubspec()
-    ]).create();
-
+    d.dir(appPath, [d.appPubspec()]).create();
     var pub = pubRun(args: ["script"]);
     pub.stderr.expect("Could not find ${p.join("bin", "script.dart")}.");
     pub.shouldExit(exit_codes.NO_INPUT);