Move kthvalue scalar test to separate method for XLA (#48042)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/48042
Moving scalar test to a separate method so the XLA team can continue to test for the other cases without failing. Requested here https://github.com/pytorch/xla/issues/2620#issuecomment-725696108
Test Plan: Imported from OSS
Reviewed By: zhangguanheng66
Differential Revision: D25055677
Pulled By: heitorschueroff
fbshipit-source-id: 5da66bac78ea197821fee0b9b8a213ff2dc19c67
