### What this PR does / why we need it? this pr implement eagle spec decoding for model runner v2, please see RFC https://github.com/vllm-project/vllm-ascend/issues/5208 ### Does this PR introduce _any_ user-facing change? No ### How was this patch tested? vLLM version: v0.13.0 --------- Signed-off-by: Ronald1995 <ronaldautomobile@163.com>