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

sdk/lib/_internal/pub_generated/test/dart2js/ignores_entrypoint_in_dependency_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 '../descriptor.dart' as d;
-import '../test_pub.dart';
-import '../serve/utils.dart';
-
-main() {
-  initConfig();
-  integration("ignores a Dart entrypoint in a dependency", () {
-    d.dir(
-        "foo",
-        [
-            d.libPubspec("foo", "0.0.1"),
-            d.dir("lib", [d.file("lib.dart", "main() => print('foo');")])]).create();
-
-    d.dir(appPath, [d.appPubspec({
-        "foo": {
-          "path": "../foo"
-        }
-      })]).create();
-
-    pubServe(shouldGetFirst: true);
-    requestShould404("web/packages/foo/lib.dart.js");
-    endPubServe();
-  });
-}