Make torch.jit.Attribute work with PYTORCH_ENABLED=0
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/23851
Test Plan: Imported from OSS
Differential Revision: D16840394
Pulled By: suo
fbshipit-source-id: b72e081513de73f565f3aeaa61125b7d3aa9c3e7
