add support for equal_nan in torch.testing.assert_close (#55788)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/55788
Test Plan: Imported from OSS
Reviewed By: albanD
Differential Revision: D27903821
Pulled By: mruberry
fbshipit-source-id: c10254b2cdc7c1ae5a31b22913136013f0472b26
