bf16 Error message cleanup as well as addition of is_bf16_supported (#63798)
Summary:
ngimel
Pull Request resolved: https://github.com/pytorch/pytorch/pull/63798
Reviewed By: heitorschueroff
Differential Revision: D30526187
Pulled By: ngimel
fbshipit-source-id: c484aec14638097c96c720095d3491249b6b2d14
