[JIT] Resolve custom classes in source importer (#32977)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/32977
ghstack-source-id: 97736042
Test Plan: Imported from OSS
Differential Revision: D19724588
fbshipit-source-id: b31b6ae14d2881d3604922e611fe4749108e674d
