Use Unicode friendly API in fused kernel related code (#49781)
Summary:
See https://github.com/pytorch/pytorch/issues/47422
Pull Request resolved: https://github.com/pytorch/pytorch/pull/49781
Reviewed By: gchanan
Differential Revision: D25847993
Pulled By: ezyang
fbshipit-source-id: e683a8d5841885857ea3037ac801432a1a3eda68
