GitLab

* Based on issue #3436. Improving _SegmentCopyKernel s GPU utilization by switching to nonzero based thread assignment

* fixing lint issues

* Update cub for cuda 11.5 compatibility (#3468)

* fixing type mismatch

* tx guaranteed to be smaller than nnz. Hence removing last check

* minor: updating comment

* adding three unit tests for csr slice method to cover some corner cases
Co-authored-by: Abdurrahman Yasar <ayasar@nvidia.com>
Co-authored-by: nv-dlasalle <63612878+nv-dlasalle@users.noreply.github.com>
Co-authored-by: Jinjing Zhou <VoVAllen@users.noreply.github.com>