Fix bug in context stores, where the store was ignored if there was a...

src/runtime.cc

Index: src/runtime.cc
===================================================================
--- src/runtime.cc	(revision 1573)
+++ src/runtime.cc	(working copy)
@@ -4432,8 +4432,10 @@
     context_ext = Handle<JSObject>(Top::context()->global());
   }
 
-  // Set the property, but ignore if read_only variable.
-  if ((attributes & READ_ONLY) == 0) {
+  // Set the property, but ignore if read_only variable on the context
+  // extension object itself.
+  if ((attributes & READ_ONLY) == 0 ||
+      (context_ext->GetLocalPropertyAttribute(*name) == ABSENT)) {
     Handle<Object> set = SetProperty(context_ext, name, value, attributes);
     if (set.is_null()) {
       // Failure::Exception is converted to a null handle in the