Object.observe: Handle oldValue for elements with accessors properly.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index de74f2ca6240d69f13fbd45df4d232a833ba3759..a63b66d49254e4787b5ee8d00afab78bb219a36a 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -1091,7 +1091,7 @@ static MaybeObject* GetOwnProperty(Isolate* isolate,
   // This could be an element.
   uint32_t index;
   if (name->AsArrayIndex(&index)) {
-    switch (obj->GetLocalElementType(index)) {
+    switch (obj->GetLocalElementKind(index)) {
       case JSObject::UNDEFINED_ELEMENT:
         return heap->undefined_value();
 
@@ -4727,7 +4727,7 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_IsPropertyEnumerable) {
 
   uint32_t index;
   if (key->AsArrayIndex(&index)) {
-    JSObject::LocalElementType type = object->GetLocalElementType(index);
+    JSObject::LocalElementKind type = object->GetLocalElementKind(index);
     switch (type) {
       case JSObject::UNDEFINED_ELEMENT:
       case JSObject::STRING_CHARACTER_ELEMENT: