Make models/functions optimized with `torch.compile` hashable

[mariosasko]

As reported in #5819, hashing functions/transforms that reference a model, or a function, optimized with torch.compile currently fails due to them not being picklable (the concrete error can be found in the linked issue).

The solutions to consider:

1. hashing/pickling the original, uncompiled version of a compiled model/function (attributes _orig_mod/_torchdynamo_orig_callable) (less precise than the 2nd option as it ignores the other params of torch.compute)
2. wait for Make compiled models serializable pytorch/pytorch#101107 to be resolved