[fix] output of `embedding_bag` with non-contiguous weight (#44032)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/43723
use weight.contiguous on fast-path as it expects contiguous tensor.
TODO:
* [x] Add tests
Pull Request resolved: https://github.com/pytorch/pytorch/pull/44032
Reviewed By: izdeby
Differential Revision: D23502200
Pulled By: glaringlee
fbshipit-source-id: 4a7b546b3e8b1ad35c287a634b4e990a1ccef874
