[runtime] Object.create(null) creates a slow object

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index 0d55fb101a59a21c4b703c9331f907bb5c97cbdd..184de03d08292f0a60efe3fce545ee8e89ed0c23 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -3528,12 +3528,13 @@ bool Genesis::InstallNatives(GlobalContextType context_type) {
       HeapObject::cast(object_function->initial_map()->prototype())->map());
 
   // Set up the map for Object.create(null) instances.
-  Handle<Map> object_with_null_prototype_map =
+  Handle<Map> slow_object_with_null_prototype_map =
       Map::CopyInitialMap(handle(object_function->initial_map(), isolate()));
-  Map::SetPrototype(object_with_null_prototype_map,
+  slow_object_with_null_prototype_map->set_dictionary_map(true);
+  Map::SetPrototype(slow_object_with_null_prototype_map,
                     isolate()->factory()->null_value());
-  native_context()->set_object_with_null_prototype_map(
-      *object_with_null_prototype_map);
+  native_context()->set_slow_object_with_null_prototype_map(
+      *slow_object_with_null_prototype_map);
 
   // Store the map for the %StringPrototype% after the natives has been compiled
   // and the String function has been set up.