Support bf16 for isinf/isnan (#5690)

Summary:
Pull Request resolved: https://github.com/pytorch/executorch/pull/5690

These two used the same pattern function.
ghstack-source-id: 245578277
exported-using-ghexport

Reviewed By: manuelcandales

Differential Revision: D63474070

fbshipit-source-id: eee8a3844757efdea58788abe07cb3694358441e