add a equality comparison helper for assert_close internals (#69750)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/69750
Test Plan: Imported from OSS
Reviewed By: ngimel
Differential Revision: D33542993
Pulled By: mruberry
fbshipit-source-id: 0de0559c33ec0f1dad205113cb363a652140b62d
