Port `tril` and `triu` to structured kernels (#67055)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/67055
This PR ports `tril` and `triu` operations to structured kernels.
ghstack-source-id: 141797608
Test Plan: Extended the existing unit tests.
Reviewed By: wanchaol
Differential Revision: D31844638
fbshipit-source-id: 03ea4aa2410b042cafc3c5397e777a9ca5351b39
