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

sdk/lib/_internal/pub_generated/test/global/binstubs/explicit_executables_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_test.dart';
-
-import '../../descriptor.dart' as d;
-import '../../test_pub.dart';
-
-main() {
-  initConfig();
-  integration("only creates binstubs for the listed executables", () {
-    d.dir("foo", [d.pubspec({
-        "name": "foo",
-        "executables": {
-          "one": "script",
-          "two": "script",
-          "three": "script"
-        }
-      }),
-          d.dir("bin", [d.file("script.dart", "main() => print('ok');")])]).create();
-
-    schedulePub(
-        args: [
-            "global",
-            "activate",
-            "--source",
-            "path",
-            "../foo",
-            "-x",
-            "one",
-            "--executable",
-            "three"],
-        output: contains("Installed executables one and three."));
-
-    d.dir(
-        cachePath,
-        [
-            d.dir(
-                "bin",
-                [
-                    d.matcherFile(binStubName("one"), contains("pub global run foo:script")),
-                    d.nothing(binStubName("two")),
-                    d.matcherFile(
-                        binStubName("three"),
-                        contains("pub global run foo:script"))])]).validate();
-  });
-}