Make dynamo.export preserve user input/output format (#90884)
Currently, dynamo flattens the user input so when user reuses the input they use for tracing, exported graph wouldn't work as it would expect flat args. This PR changes this behaviour by explicitly wrapping the dynamo produced graph with correct user input/output format.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/90884
Approved by: https://github.com/zhxchen17, https://github.com/voznesenskym
