[fx] persist `tracer_cls` on `fx.Graph` when deep copying (#63353)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/63353
Custom deepcopy method copies all nodes but does not copy the tracer_cls attribute
Reviewed By: houseroad
Differential Revision: D30349424
fbshipit-source-id: 3e98bdac8a8a992eb0b4ec67fe80bb2e5cf3884d
