[FX][1.8] Cherrypick three FX fixes to 1.8 (#52021)
* Fix leaf modules in Transformer
[ghstack-poisoned]
* Fix tuple type annotations
[ghstack-poisoned]
* Generalize dict key check in `create-arg` (#51927)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/51927
Test Plan: Imported from OSS
Reviewed By: pbelevich
Differential Revision: D26329655
Pulled By: jamesr66a
fbshipit-source-id: a15e7d9564551521af12a8fde1c7524856f0cbc2
