[es6] Partially implement Reflect.getOwnPropertyDescriptor.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 226878cda43b97f8a427d7125c1214c1fa2e2945..5c9241d50b3c96fd0f1ca2fd62f3514f2a4bd839 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -6576,7 +6576,7 @@ bool JSArray::ArraySetLength(Isolate* isolate, Handle<JSArray> a,
 
 // static
 bool JSReceiver::GetOwnPropertyDescriptor(Isolate* isolate,
-                                          Handle<JSObject> object,
+                                          Handle<JSReceiver> object,
                                           Handle<Object> key,
                                           PropertyDescriptor* desc) {
   bool success = false;