Add equality comparison to c10::Dict (#34892)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/34892
Same rationale and implementation as in
https://github.com/pytorch/pytorch/pull/34856
Test Plan: Imported from OSS
Differential Revision: D20493169
Pulled By: suo
fbshipit-source-id: 46d79a4ff5d4af2964cfaeb2c43f56decadf3201
