Use native async/await support in pub.

sdk/lib/_internal/pub_generated/test/dart2js/ignores_entrypoints_in_lib_test.dart

-// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS d.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 '../descriptor.dart' as d;
-import '../test_pub.dart';
-import '../serve/utils.dart';
-
-main() {
-  initConfig();
-  setUp(() {
-    d.dir(
-        appPath,
-        [
-            d.appPubspec(),
-            d.dir('lib', [d.file('file.dart', 'void main() => print("hello");'),]),
-            d.dir('web', [d.file('index.html', 'html'),])]).create();
-  });
-
-  integration("build ignores Dart entrypoints in lib", () {
-    schedulePub(
-        args: ["build", "--all"],
-        output: new RegExp(r'Built 1 file to "build".'));
-
-    d.dir(appPath, [d.dir('build', [d.nothing('lib')])]).validate();
-  });
-
-  integration("serve ignores Dart entrypoints in lib", () {
-    pubServe();
-    requestShould404("packages/myapp/main.dart.js");
-    endPubServe();
-  });
-
-}