CUDA BFloat div, addcdiv, addcmul, mean, var (#44758)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/44758
Reviewed By: mruberry
Differential Revision: D23752317
Pulled By: ngimel
fbshipit-source-id: 77992cf991f4e2b4b6839de73ea7e6ce2e1061c6
