This PR moves the communication operation of shared experts out of extra stream because I found that this might cause rtMemcpy related errors when running shared experts multistream with aclgraph. Furthermore, I utilize a global variable as extra stream object to avoid allocating streams for each layer in full-graph mode. - vLLM version: v0.11.0rc3 - vLLM main: https://github.com/vllm-project/vllm/commit/v0.11.0 Signed-off-by: whx-sjtu <2952154980@qq.com>