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

sdk/lib/_internal/pub_generated/test/build/copies_non_dart_files_to_build_test.dart

Index: sdk/lib/_internal/pub_generated/test/build/copies_non_dart_files_to_build_test.dart
diff --git a/sdk/lib/_internal/pub_generated/test/build/copies_non_dart_files_to_build_test.dart b/sdk/lib/_internal/pub_generated/test/build/copies_non_dart_files_to_build_test.dart
deleted file mode 100644
index ab808b710e59430075c66f05498b6af7c52d9d79..0000000000000000000000000000000000000000
--- a/sdk/lib/_internal/pub_generated/test/build/copies_non_dart_files_to_build_test.dart
+++ /dev/null
@@ -1,44 +0,0 @@
-// Copyright (c) 2013, 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 '../descriptor.dart' as d;
-import '../test_pub.dart';
-
-main() {
-  initConfig();
-
-  integration("copies non-Dart files to build/", () {
-    servePackages((builder) => builder.serve("browser", "1.0.0"));
-
-    d.dir(
-        appPath,
-        [// A browser dependency with no entrypoints shouldn't cause dart.js to be
-      // copied in.
-      d.appPubspec({
-        "browser": "1.0.0"
-      }),
-          d.dir(
-              'web',
-              [
-                  d.file('file.txt', 'contents'),
-                  d.dir('subdir', [d.file('subfile.txt', 'subcontents')])])]).create();
-
-    schedulePub(
-        args: ["build"],
-        output: new RegExp(r'Built 2 files to "build".'));
-
-    d.dir(
-        appPath,
-        [
-            d.dir(
-                'build',
-                [
-                    d.dir(
-                        'web',
-                        [
-                            d.nothing('packages'),
-                            d.file('file.txt', 'contents'),
-                            d.dir('subdir', [d.file('subfile.txt', 'subcontents')])])])]).validate();
-  });
-}