fix searchsorted output type (#42933)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/41389
Make sure searchsorted that returns integer type does not make them require gradients.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/42933
Reviewed By: gchanan
Differential Revision: D23109583
Pulled By: albanD
fbshipit-source-id: 5af300b2f7f3c140d39fd7f7d87799f7b93a79c1
