Fix bench-diskIO.
Fix bench-diskIO.

When `mingw32_HOST_OS`, the type `CFilePath` defined as `CWString` rather than `CString`.

Signed-off-by: Tao He <9e9d50aa3fb60f0eb719baf23d12c62f0c16e40a@gmail.com>

winterland1989/stdio,winterland1989/stdio,winterland1989/stdio