Fix GC error in ES5 read-only properties implementation.

src/handles.h

Index: src/handles.h
===================================================================
--- src/handles.h	(revision 5675)
+++ src/handles.h	(working copy)
@@ -193,6 +193,10 @@
 void NormalizeElements(Handle<JSObject> object);
 void TransformToFastProperties(Handle<JSObject> object,
                                int unused_property_fields);
+void NumberDictionarySet(Handle<NumberDictionary> dictionary,
+                         uint32_t index,
+                         Handle<Object> value,
+                         PropertyDetails details);
 
 // Flattens a string.
 void FlattenString(Handle<String> str);