Add VmapInterpreter.randomness (in pyfunctorch) provide it in info object (#90789)
This PR:
- adds VmapInterpreter.randomness. This returns the randomness option
the user provided in vmap(..., randomness=...)
- adds randomness in the info object passed to the vmap staticmethod of
autograd.Function. This is so that the user can handle random operations
on their own terms (if randomness="error", and if the autograd.Function
has random operations, then it is the user's responsiblity to raise an
error).
Test Plan:
- updated unittest
Pull Request resolved: https://github.com/pytorch/pytorch/pull/90789
Approved by: https://github.com/samdow, https://github.com/soulitzer
