[jit] small cleanups after script:: removal (#34677)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/34677
1. Remove remaining uses of `script::` namespace from the codebase,
2. Add one more typedef for `script::ExtraFilesMap` which is part of the
public interface.
Pull Request resolved: #34580
Test Plan: Imported from OSS
Reviewed By: zdevito
Differential Revision: D20431739
Pulled By: suo
fbshipit-source-id: a29d369c755b6506c53447ca1f286b6339222c9a
