[Kernel] Refactor FlashInfer allreduce for mnnvl backend (#34109)
Signed-off-by: hjjq <50634613+hjjq@users.noreply.github.com>
Signed-off-by: wzhao18 <wzhao18.sz@gmail.com>
Co-authored-by: wzhao18 <wzhao18.sz@gmail.com>
Co-authored-by: Wei Zhao <51183510+wzhao18@users.noreply.github.com>
