### What this PR does / why we need it?
This PR fixes the bug for eagle3 and cp enable introduced by the
parallel speculative inference PR.
### Does this PR introduce _any_ user-facing change?
no
### How was this patch tested?
tests and ut
- vLLM version: v0.17.0
- vLLM main:
4034c3d32e
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Signed-off-by: lilinsiman <lilinsiman@gmail.com>