[test_c10d] Add wait in nccl high priority stream test (#54714)
Summary:
Add wait in test_pass_nccl_options_high_priority_stream
after the all reduce operation.
Without wait, the allreduce operation might be still running and the
comparison of result might not be valid.
Signed-off-by: Jagadish Krishnamoorthy <jagdish.krishna@gmail.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/54714
Reviewed By: ezyang
Differential Revision: D27379544
fbshipit-source-id: 6393d25f8f3d5635c5d34c9b3aac8b801315b48e
