Disallow annotations on instance attributes outside __init__ (#67051)
Summary:
**Summary**: This commit solves the first part of https://github.com/pytorch/pytorch/issues/52306, which disallows type annotations on instance attributes inside any method other than the constructor.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/67051
Test Plan:
Added test to test_types.py.
**Reviewers**: Zhengxu Chen
**Subscribers**: Zhengxu Chen, Yanan Cao, Peng Wu, Yining Lu
**Tasks**: T103941984
**Tags**: pytorch
**Fixes** https://github.com/pytorch/pytorch/issues/52306
Reviewed By: zhxchen17
Differential Revision: D31843527
Pulled By: andrewor14
fbshipit-source-id: 624879ae801621e367c59228be8b0581ecd30ef4
