Add bfloat support for torch.randn and torch.norm (#47143)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/47143
Reviewed By: pbelevich
Differential Revision: D24664407
Pulled By: malfet
fbshipit-source-id: c63ff1cbb812751aba4c56e64e6ee1008cfc2d7f
