[PyTorch] Avoid some extra intrusive_ptr<Tuple> copies in Unpickler (#51902)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/51902
These seem like straightforward improvements. (I don't have measurements; feel free to reject if you're skeptical)
ghstack-source-id: 121278775
Test Plan: CI
Reviewed By: qizzzh
Differential Revision: D26322438
fbshipit-source-id: d393a32cc34bb68bc4f804f4b1cc5a8af27763c9
