Use native async/await support in pub.

sdk/lib/_internal/pub_generated/test/serve/does_not_watch_compiled_js_files_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.
-
-library pub_tests;
-
-import '../descriptor.dart' as d;
-import '../test_pub.dart';
-import 'utils.dart';
-
-main() {
-  initConfig();
-  integration("does not watch changes to compiled JS files in the package", () {
-    d.dir(
-        appPath,
-        [d.appPubspec(), d.dir("web", [d.file("index.html", "body")])]).create();
-
-    pubServe();
-    waitForBuildSuccess();
-    requestShouldSucceed("index.html", "body");
-
-    d.dir(
-        appPath,
-        [
-            d.dir(
-                "web",
-                [
-                    d.file('file.dart', 'void main() => print("hello");'),
-                    d.file("other.dart.js", "should be ignored"),
-                    d.file("other.dart.js.map", "should be ignored"),
-                    d.file("other.dart.precompiled.js", "should be ignored")])]).create();
-
-    waitForBuildSuccess();
-    requestShouldSucceed("file.dart", 'void main() => print("hello");');
-    requestShould404("other.dart.js");
-    requestShould404("other.dart.js.map");
-    requestShould404("other.dart.precompiled.js");
-    endPubServe();
-  });
-}