Fix Binomimal overflow when logits is large (#20679)
Summary:
This PR fixes #17843. In addition (test locally), this still maintains the continuity of log_prob which is addressed in https://github.com/pytorch/pytorch/pull/15962
cc neerajprad
Pull Request resolved: https://github.com/pytorch/pytorch/pull/20679
Differential Revision: D15413311
Pulled By: ezyang
fbshipit-source-id: 4fc0ca755ae6a85aa7deb2206dab675f82f9aa25
