Ensure correct enumeration indices in the dict

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 45a2ac0d8fea0a40b462f824a013b2e0489c919b..b3b2b3872f95cf3ac9a188a1a388d86ebfc06042 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -3027,6 +3027,9 @@ class Dictionary: public HashTable<Shape, Key> {
 
   // Set the details for entry.
   void DetailsAtPut(int entry, PropertyDetails value) {
+    ASSERT(value.dictionary_index() != 0 ||
+           value.IsDontEnum() ||
+           value.IsDeleted());
     this->set(HashTable<Shape, Key>::EntryToIndex(entry) + 2, value.AsSmi());
   }