[FX] __str__ for GraphModule and Graph (#44166)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/44166
Test Plan: Imported from OSS
Reviewed By: ZolotukhinM
Differential Revision: D23520801
Pulled By: jamesr66a
fbshipit-source-id: f77e3466e435127ec01e66291964395f32a18992
