[fx] store Tracer class on Graph and GraphModule for package deserialization (#62497)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/62497
Previously named: add support for custom tracer in __reduce_package__
Stores a Tracer class on a Graph created by Tracer, and copies the Tracer class into the GraphModule's state so that when a GraphModule is packaged by torch package, it can be reconstructed with the same Tracer and GraphModule class name.
Reviewed By: suo
Differential Revision: D30019214
fbshipit-source-id: eca09424ad30feb93524d481268b066ea55b892a
