Use native async/await support in pub.

sdk/lib/_internal/pub_generated/test/upgrade/report/highlights_overrides_test.dart

Index: sdk/lib/_internal/pub_generated/test/upgrade/report/highlights_overrides_test.dart
diff --git a/sdk/lib/_internal/pub_generated/test/upgrade/report/highlights_overrides_test.dart b/sdk/lib/_internal/pub_generated/test/upgrade/report/highlights_overrides_test.dart
deleted file mode 100644
index 4b567f4bec791c0bd676ccc8eb59c0c41f987f2f..0000000000000000000000000000000000000000
--- a/sdk/lib/_internal/pub_generated/test/upgrade/report/highlights_overrides_test.dart
+++ /dev/null
@@ -1,28 +0,0 @@
-// Copyright (c) 2013, 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.
-
-library pub_tests;
-
-import '../../descriptor.dart' as d;
-import '../../test_pub.dart';
-
-main() {
-  initConfig();
-  integration("highlights overridden packages", () {
-    servePackages((builder) => builder.serve("overridden", "1.0.0"));
-
-    d.dir(appPath, [d.pubspec({
-        "name": "myapp",
-        "dependency_overrides": {
-          "overridden": "any"
-        }
-      })]).create();
-
-    // Upgrade everything.
-    pubUpgrade(output: new RegExp(r"""
-Resolving dependencies\.\.\..*
-! overridden 1\.0\.0 \(overridden\)
-""", multiLine: true));
-  });
-}