Revert D30735341: Migrate uses of THCReduceApplyUtils to cuda_utils::BlockReduce
Test Plan: revert-hammer
Differential Revision:
D30735341 (https://github.com/pytorch/pytorch/commit/a5ad08ec704a3f765814eacf5c393e871c0174e1)
Original commit changeset: 3cb58bed8f1f
fbshipit-source-id: 874dd0f93b24a99694db42a15714834069d402bc
