dart:io | Add FileSystemEntity.stat() and FileStat class.

runtime/bin/file_system_entity_patch.dart

Index: runtime/bin/file_system_entity_patch.dart
diff --git a/runtime/bin/file_system_entity_patch.dart b/runtime/bin/file_system_entity_patch.dart
index 13a7dc8da7ed0a12812488fe35609cfc44aa3d8a..2c2b324a20fb5a78fc99e43cef9017503ca23c24 100644
--- a/runtime/bin/file_system_entity_patch.dart
+++ b/runtime/bin/file_system_entity_patch.dart
@@ -2,6 +2,11 @@
 // 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.
 
+patch class FileStat {
+  /* patch */ static List<int> _statSync(String path) native "File_Stat";
+}
+
+
 patch class FileSystemEntity {
   /* patch */ static _getType(String path, bool followLinks)
       native "File_GetType";