* Refactor primitive test to support multiple GPUs in rings
* Make GPUs sync before transfer optional
* Use same ring format as RCCL
* Extend to 8 GPUs and report errors if there is no P2P access
* Control GPUs sync before ops from command line with "-s" option
* Change buffer size through command line option "-n"
Rename iterations command line option to "-i"
[ROCm/rccl commit: 70804da15b]
gilbertlee-amd
Wenkai Du