adding IterableDataset to utils.data.__init__ (#33543)
Summary:
this shall fix issue https://github.com/pytorch/pytorch/issues/27820 again
Pull Request resolved: https://github.com/pytorch/pytorch/pull/33543
Differential Revision: D20002446
Pulled By: vincentqb
fbshipit-source-id: 7563a56fd6238efe8ea5626b02ba5e8fcda0780e
