Kill dead code in common_nn as part of merging Criterion and NewCriterionTests. (#43956)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/43956
See https://github.com/pytorch/pytorch/pull/43769 and https://github.com/pytorch/pytorch/pull/43776 for proof this code is dead.
Test Plan: Imported from OSS
Reviewed By: mruberry
Differential Revision: D23452217
Pulled By: gchanan
fbshipit-source-id: 6850aab2daaa1c321a6b7714f6f113f364f41973
