Adding alltoall_single collective to collective quantization API (#63154)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/63154
The collective quantization API now supports alltoall, alltoall_single, and allscatter. The test is also included.
ghstack-source-id: 136856877
Test Plan: buck test mode/dev-nosan //caffe2/test/distributed/algorithms/quantization:DistQuantizationTests_nccl -- test_all_to_all_single_bfp16
Reviewed By: wanchaol
Differential Revision: D30255251
fbshipit-source-id: 856f4fa12de104689a03a0c8dc9e3ecfd41cad29
