dart:io | Add FileSystemEntity.typeSync to test for symbolic links.

runtime/bin/file_system_entity_patch.dart

Index: runtime/bin/file_system_entity_patch.dart
diff --git a/tests/lib/async/deferred/deferred_api_library.dart b/runtime/bin/file_system_entity_patch.dart
similarity index 63%
copy from tests/lib/async/deferred/deferred_api_library.dart
copy to runtime/bin/file_system_entity_patch.dart
index b59077065dc8212ef534fa68b211f0e705126ff7..267ab1b5fb94ab2b265c55b46fc0bbe5f80a7451 100644
--- a/tests/lib/async/deferred/deferred_api_library.dart
+++ b/runtime/bin/file_system_entity_patch.dart
@@ -2,11 +2,7 @@
 // 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.
 
-// Imported by deferred_api_test.dart.
-
-library deferred_api_library;
-
-foo(x) {
-  print('foo($x)');
-  return 42;
+patch class FileSystemEntity {
+  /* patch */ static int _getType(String path, bool followLinks)
+      native "File_GetType";
 }