Use native async/await support in pub.

sdk/lib/_internal/pub_generated/test/validator/size_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 'dart:async';
-import 'dart:math' as math;
-
-import 'package:scheduled_test/scheduled_test.dart';
-
-import '../../lib/src/validator/size.dart';
-import '../descriptor.dart' as d;
-import '../test_pub.dart';
-import 'utils.dart';
-
-Function size(int size) {
-  return (entrypoint) => new SizeValidator(entrypoint, new Future.value(size));
-}
-
-main() {
-  initConfig();
-
-  setUp(d.validPackage.create);
-
-  integration('should consider a package valid if it is <= 10 MB', () {
-    expectNoValidationError(size(100));
-    expectNoValidationError(size(10 * math.pow(2, 20)));
-  });
-
-  integration('should consider a package invalid if it is more than 10 MB', () {
-    expectValidationError(size(10 * math.pow(2, 20) + 1));
-  });
-}