mkdir when destination directory doesn't exist (#9060)

Fixes #8980

Make sure we mkdir if destination directory doesn't exist. I have no
idea why it doesn't work before

ghstack-source-id: 745e02d5e147f67927a86ccb25a4330e2aceeccd
Pull Request resolved: https://github.com/pytorch/executorch/pull/9055

Co-authored-by: Mengwei Liu <larryliu@fb.com>