Maybe use reference stash to replace record stream to reduce mem peak

Due to behavior of CudaCacheAllocator, record stream will lead to a late memory free, which has significant on memory peak. (Could refer to [fsdp1's issue due to recordstream](https://dev-discuss.pytorch.org/t/fsdp-cudacachingallocator-an-outsider-newb-perspective/1486)). In Pytorch 2.8 +，[c10d has remove all recordStream in collective communication](https://github.com/pytorch/pytorch/blob/main/torch/csrc/distributed/c10d/ProcessGroupNCCL.cpp#L2910). Thus, I wonder if there are plans to remove record stream and use reference stash to handle multistream scenario?