### What this PR does / why we need it?
add the UT of pcp and dcp in the attention_cp file
### Does this PR introduce _any_ user-facing change?
no
### How was this patch tested?
- vLLM version: v0.12.0
- vLLM main:
ad32e3e19c
---------
Signed-off-by: pichangping <1337510399@qq.com>
### What this PR does / why we need it?
Adding UT for DCP/PCP
-vLLM version: v0.12.0
-vLLM main:
ad32e3e19c
Signed-off-by: zengran <zengran2@huawei.com>