Revert "Revert "Use native async/await support in pub.""

sdk/lib/_internal/pub_generated/test/validator/utf8_readme_test.dart

-// 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.
-
-import 'package:scheduled_test/scheduled_test.dart';
-
-import '../../lib/src/entrypoint.dart';
-import '../../lib/src/validator.dart';
-import '../../lib/src/validator/utf8_readme.dart';
-import '../descriptor.dart' as d;
-import '../test_pub.dart';
-import 'utils.dart';
-
-Validator utf8Readme(Entrypoint entrypoint) =>
-    new Utf8ReadmeValidator(entrypoint);
-
-main() {
-  initConfig();
-
-  group('should consider a package valid if it', () {
-    setUp(d.validPackage.create);
-
-    integration('looks normal', () => expectNoValidationError(utf8Readme));
-
-    integration('has a non-primary readme with invalid utf-8', () {
-      d.dir(
-          appPath,
-          [
-              d.file("README", "Valid utf-8"),
-              d.binaryFile("README.invalid", [192])]).create();
-      expectNoValidationError(utf8Readme);
-    });
-  });
-
-  integration(
-      'should consider a package invalid if it has a README with ' 'invalid utf-8',
-      () {
-    d.validPackage.create();
-
-    d.dir(appPath, [d.binaryFile("README", [192])]).create();
-    expectValidationWarning(utf8Readme);
-  });
-}