Made Collector.collect() return immediately for disabled related collection.

django/db/models/deletion.py

@@ -210,7 +210,9 @@ class Collector:
                                  source_attr=ptr.remote_field.related_name,
                                  collect_related=False,
                                  reverse_dependency=True)
-        if collect_related:
+        if not collect_related:
+            return
+
         if keep_parents:
             parents = set(model._meta.get_parent_list())
         for related in get_candidate_relations_to_delete(model._meta):
@@ -242,6 +244,7 @@ class Collector:
                         sub_objs = sub_objs.only(*tuple(referenced_fields))
                     if sub_objs:
                         field.remote_field.on_delete(self, field, sub_objs, self.using)
+
         for field in model._meta.private_fields:
             if hasattr(field, 'bulk_related_objects'):
                 # It's something like generic foreign key.