[CI/Test] Fix FP8 per-tensor quant test reference scale shape

[LucasWilkinson]

Summary

Fixes test_dynamic_per_tensor_fp8_quant that was broken by #30257. (CI failure: https://buildkite.com/organizations/vllm/pipelines/ci/builds/42664/jobs/019b03c9-8e5a-4fb8-baec-7ba031141cbf/log)

Issue

#30257 changed ops.scaled_fp8_quant to return scale with shape [1] instead of [1, 1]. However, the test's reference function ref_dynamic_per_tensor_fp8_quant was not updated to match, causing all test_dynamic_per_tensor_fp8_quant tests to fail with:

AssertionError: The values for attribute 'shape' do not match: torch.Size([1, 1]) != torch.Size([1]).

Fix

Updated ref_dynamic_per_tensor_fp8_quant in tests/kernels/quant_utils.py to return scale with shape [1] instead of [1, 1], matching the new behavior of the ops implementation.

Testing

pytest tests/kernels/quantization/test_fp8_quant.py -v
# 109 passed

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[gemini-code-assist]

Code Review

This pull request addresses a test failure in test_dynamic_per_tensor_fp8_quant by correcting the shape of the returned scale in the reference implementation ref_dynamic_per_tensor_fp8_quant. The change modifies ref_scale.view((1, 1)) to ref_scale.view(1), which aligns the test's reference function with the updated behavior of ops.scaled_fp8_quant that now returns a scale of shape [1]. This is a correct and necessary fix to ensure the CI/test suite passes. The change is minimal and directly targets the described issue.