Have _embedding_bag_dense_backward match JIT signature. (#19522)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/19522
ghimport-source-id: ad645d87396de645a1aff5fd9d9939cb79cf6558
Differential Revision: D15021419
Pulled By: gchanan
fbshipit-source-id: bd7017edadb4ec9d43cefddf0aee8c52c5cca6a4
