Changes to prepare for fake tensors on in functorch by default (#84432)
Fixes some errors you run into in dynamo when turning on fake tensors. I'm waiting on flipping the switch because I need to also get some fixes into dynamo + do benchmarking.
I could manually turn off fake tensors in functorch in dynamo, and then turn it on here if requested, although the changes here are pretty minimal.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/84432
Approved by: https://github.com/Chillee
