Make aten_to_numpy_dtype in tensor_numpy.h public. (#23943)
Summary:
The corresponding numpy_dtype_to_aten is public already so this
should be fine. Tests still pass.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/23943
Differential Revision: D16690742
Pulled By: soumith
fbshipit-source-id: 81431a3316509cff8a9122e10e8f6a362bbcc9c0
