Use native async/await support in pub.

sdk/lib/_internal/pub_generated/test/global/binstubs/name_collision_with_overwrite_test.dart

-// Copyright (c) 2014, 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_stream.dart';
-import 'package:scheduled_test/scheduled_test.dart';
-
-import '../../descriptor.dart' as d;
-import '../../test_pub.dart';
-
-main() {
-  initConfig();
-  integration("overwrites an existing binstub if --overwrite is passed", () {
-    d.dir("foo", [d.pubspec({
-        "name": "foo",
-        "executables": {
-          "foo": "foo",
-          "collide1": "foo",
-          "collide2": "foo"
-        }
-      }),
-          d.dir("bin", [d.file("foo.dart", "main() => print('ok');")])]).create();
-
-    d.dir("bar", [d.pubspec({
-        "name": "bar",
-        "executables": {
-          "bar": "bar",
-          "collide1": "bar",
-          "collide2": "bar"
-        }
-      }),
-          d.dir("bin", [d.file("bar.dart", "main() => print('ok');")])]).create();
-
-    schedulePub(args: ["global", "activate", "-spath", "../foo"]);
-
-    var pub =
-        startPub(args: ["global", "activate", "-spath", "../bar", "--overwrite"]);
-    pub.stdout.expect(
-        consumeThrough("Installed executables bar, collide1 and collide2."));
-    pub.stderr.expect("Replaced collide1 previously installed from foo.");
-    pub.stderr.expect("Replaced collide2 previously installed from foo.");
-    pub.shouldExit();
-
-    d.dir(
-        cachePath,
-        [
-            d.dir(
-                "bin",
-                [
-                    d.matcherFile(binStubName("foo"), contains("foo:foo")),
-                    d.matcherFile(binStubName("bar"), contains("bar:bar")),
-                    d.matcherFile(binStubName("collide1"), contains("bar:bar")),
-                    d.matcherFile(binStubName("collide2"), contains("bar:bar"))])]).validate();
-  });
-}