[Bugfix] Fix NVFP4/OCP MX MoE emulation

[mawong-amd]

Purpose

This PR fixes an issue in the NVFP4/OCP MX MoE emulation code paths caused by #42120.
In that PR, TritonExperts.apply in vllm/model_executor/layers/fused_moe/experts/triton_moe.py was modified to call moe_kernel_quantize_input on the activations if TritonExperts.expects_unquantized_inputs == True. However, this flag is pre-set to True for NVFP4 and OCP MX emulation code paths, which also call moe_kernel_quantize_input on activations before entering TritonExperts.apply. The end-result is that moe_kernel_quantize_input is erroneously called twice on activations when NVFP4/OCP MX emulation is active.

Test Plan

NVFP4 emulation is tested by the following
pytest -s -v evals/gsm8k/test_gsm8k_correctness.py --config-list-file=configs/models-mi3xx.txt
which loads a NVFP4-quantized model (nvidia/Qwen3-30B-A3B-FP4) and runs it in emulation mode on a AMD gfx942 based machine. This is run as part of AMD CI in the AMD: LM Eval Large Models (H200) (mi300_8) test group.

Test Result

The above test group passes.

cc: @AndreasKaratzas. Also @fxmarty-amd, who noticed the same errors and has pending fixes for it in #46142 (for OCP MX) and #44667 (for NVFP4)

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Essential Elements of an Effective PR Description Checklist

• The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
• The test plan, such as providing test command.
• The test results, such as pasting the results comparison before and after, or e2e results
• (Optional) The necessary documentation update, such as updating supported_models.md and examples for a new model.

[AndreasKaratzas]

LGTM

Thank you for fixing that issue.

[fxmarty-amd]

@AndreasKaratzas @mawong-amd I think this PR is not sufficient, especially regarding:

vllm/vllm/model_executor/layers/fused_moe/experts/triton_moe.py

Line 340 in 6871738

a1q_scale if a1q_scale is not None else self.a1_scale,

See the comment about it at #44667 (comment)

[fxmarty-amd]

The PR at #46142 should fix that (self.a1_scale being wrongfully used in emulation case)

[fxmarty-amd]

Results in:

(EngineCore pid=3325911)   File "/felmarty/repos/vllm/vllm/model_executor/layers/fused_moe/experts/triton_moe.py", line 248, in apply
(EngineCore pid=3325911)     self.a1_scale or self.a1_gscale,
(EngineCore pid=3325911)     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=3325911) torch.AcceleratorError: HIP error: operation not permitted when stream is capturing
(EngineCore pid=3325911) Search for `hipErrorStreamCaptureUnsupported' in https://rocm.docs.amd.com/projects/HIP/en/latest/index.html for more information.
(EngineCore pid=3325911) HIP kernel errors might be asynchronously reported at some other API call, so the stacktrace below might be incorrect.
(EngineCore pid=3325911) For debugging consider passing AMD_SERIALIZE_KERNEL=3
(EngineCore pid=3325911) Compile with `TORCH_USE_HIP_DSA` to enable device-side assertions.
(EngineCore pid=3325911)
[rank0]:[W625 14:59:32.481659036 ProcessGroupNCCL.cpp:1554] Warning: WARNING: destroy_process_group() was not called before program exit, which can leak resources. For more info, please see https://pytorch.org/docs/stable/distributed.html#shutdown (function operator())