Use Unicode friendly API on Win32 in THAllocator (#47905)
Summary:
This replaces the narrow character set APIs with the wide character set ones in `THAllocator.cpp`. This fixes the potential crashes caused by passing non-ASCII characters in `torch::from_file` on Windows.
See: https://github.com/pytorch/pytorch/issues/47422
Pull Request resolved: https://github.com/pytorch/pytorch/pull/47905
Reviewed By: zhangguanheng66
Differential Revision: D25399146
Pulled By: ezyang
fbshipit-source-id: 0a183b65de171c48ed1718fa71e773224eaf196f
