[test] Lower number of top logprobs to get rid of -inf

[ByronHsu]

Motivation

One of the latest CI failed (test_srt_endpoint_with_penalizers.py) https://github.com/sgl-project/sglang/actions/runs/13006304270/job/36334676037.

This is a known issue #2955. In short, if the returned logprob contains -inf, fastapi will crash because it cannot handle -inf by default (fastapi/fastapi#8912).

The latest rope implementation makes the distribution more spiky likely due to the higher precision (now rope uses fp32, but before was bf16). The correctness is guaranteed as all other tests have passed.

The temporary solution is to lower top_logprobs_num because if the number is large, it is more likely the latter probs will be -inf, especially with penalty. e.g

This PR is to fix the CI. In the meantime, I will see if i can add a threshold for the logit processor or make fastapi able to handle -inf

Modifications

Checklist

• Format your code according to the Code Formatting with Pre-Commit.
• Add unit tests as outlined in the Running Unit Tests.
• Update documentation / docstrings / example tutorials as needed, according to Writing Documentation.
• Provide throughput / latency benchmark results and accuracy evaluation results as needed, according to Benchmark and Profiling.

[ByronHsu]

@zhyncs let's see if the CI can pass. It is constantly passing on my local h100.

[ByronHsu]

@zhyncs it passed