[Scheduler] validate max_num_batched_tokens and max_model_len in AscendSchedulerConfig

[linfeng-yuan]

What this PR does / why we need it?

Add configuration check logic for ascend scheduler: if chunked_prefill is disabled, max_num_batched_tokens couldn't be less than max_model_len, following vLLM;

Does this PR introduce any user-facing change?

users cannot set max_num_batched_tokens smaller than max_model_len with ascend scheduler

How was this patch tested?

CI and vllm serving passed

• vLLM version: v0.10.0
• vLLM main: vllm-project/vllm@f77a080

[gemini-code-assist]

Code Review

This pull request introduces a validation check in AscendSchedulerConfig to prevent configurations where max_num_batched_tokens is less than max_model_len when chunked prefill is disabled. This is a valuable correctness fix that avoids unexpected rejection of long sequences. The implementation is sound, and the associated test updates and additions are thorough, covering both valid and invalid scenarios. The changes improve the robustness and user-friendliness of the scheduler configuration.

[github-actions]

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 77.39%. Comparing base (1de16ea) to head (3ed37b2).
⚠️ Report is 12 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2434      +/-   ##
==========================================
+ Coverage   77.37%   77.39%   +0.01%     
==========================================
  Files         128      128              
  Lines       16455    16468      +13     
==========================================
+ Hits        12732    12745      +13     
  Misses       3723     3723              

Flag	Coverage Δ
unittests	77.39% <100.00%> (+0.01%)	⬆️

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[wangxiyuan]

please update the commit message. Thanks