Make methods of internal file_obj visible from StreamWrapper (#71653)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/71653
Test Plan: Imported from OSS
Reviewed By: NivekT
Differential Revision: D33718749
Pulled By: ejguan
fbshipit-source-id: f3a8244f22ca37049b8678afa0e329b23c957a9d
(cherry picked from commit a4d12ca48ec153ad5f058152e7df4a9a1421b184)
