[runtime] Store constructor function index on primitive maps.

src/runtime/runtime-collections.cc

Index: src/runtime/runtime-collections.cc
diff --git a/src/runtime/runtime-collections.cc b/src/runtime/runtime-collections.cc
index 1ba1e34356caf5d93e425c7f3b0e6c337b655107..b8a97c79469bbae9c54225c6fdf9d11a9750acb8 100644
--- a/src/runtime/runtime-collections.cc
+++ b/src/runtime/runtime-collections.cc
@@ -299,7 +299,7 @@ RUNTIME_FUNCTION(Runtime_MapIteratorNext) {
 
 void Runtime::WeakCollectionInitialize(
     Isolate* isolate, Handle<JSWeakCollection> weak_collection) {
-  DCHECK(weak_collection->map()->inobject_properties() == 0);
+  DCHECK_EQ(0, weak_collection->map()->GetInObjectProperties());
   Handle<ObjectHashTable> table = ObjectHashTable::New(isolate, 0);
   weak_collection->set_table(*table);
 }