ProcessGroupUCC tests (#83285)
- [x] Direct dependency on UCX is completely removed, UCC active set API always enabled
- [x] Remove `TORCH_UCC_PROFILING_ENABLE`, always enable profiling
- [x] Fixes profiling of `recv` and `all_gather`
- [x] Use the NCCL TL of UCC on CUDA, as the UCP TL is not well supported on CUDA
Most tests are passing, but there are a few skipped tests:
- `scatter` and `gather` are not supported by the UCP TL of UCC on CPU tensors
- A few flaky tests in PyTorch's CI environment
- Profiler-related failures, some of them will be fixed by @Fuzzkatt in https://github.com/pytorch/pytorch/pull/84368
After this PR is merged, I will continue to work on these skipped failures.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/83285
Approved by: https://github.com/vtlam, https://github.com/malfet, https://github.com/kwen2501
