Fix `UNICODE` conflict on Windows (#28782)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/27568.
cc IlyaOvodov.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/28782
Differential Revision: D18201449
Pulled By: ezyang
fbshipit-source-id: 404e7c0abdfeef52a0e81ab2acd1b61e86c28f39
