Move THCTensor_{normal, normal_means, normal_stddevs, normal_means_stddevs} to ATen (#20621)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/20621
ghimport-source-id: f461d7f1eb6b5a8306dd8175cbb0a7fcc9f64c76
Differential Revision: D15454048
Pulled By: ezyang
fbshipit-source-id: 8bfc57bf015b85f57ed99a54176926386aab4e34