Revert "Sort: Use cub::WarpMergeSort for small sorts (32 < n <= 128) (#96223)"
This reverts commit 5d8c7e7ea47cb6e1faf333430889a804de87536e.
Reverted https://github.com/pytorch/pytorch/pull/96223 on behalf of https://github.com/osalpekar due to Causing numerous Internal build failures emerging from SortUtils.cuh. Details in [D44378546](https://www.internalfb.com/diff/D44378546)
