Fix fake metadata for CuTeDSL 32x1 MXFP8 quantization

[alexsamardzic]

Stack from ghstack (oldest at bottom):

• Wire MoE and MXFP8Linear training paths to CuTeDSL by default #4620
• Add CuTeDSL MXFP8 K-groups scale rearrange kernel #4604
• Add CuTeDSL MXFP8 pad/unpad kernels #4594
• -> Fix fake metadata for CuTeDSL 32x1 MXFP8 quantization #4589
• Add CuTeDSL MXFP8 M-groups scale rearrange kernel #4585

[pytorch-bot]

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✅ You can merge normally! (5 Unrelated Failures)

As of commit 02aad22 with merge base 3818749 ():

FLAKY - The following job failed but was likely due to flakiness present on trunk:

• Run Regression Tests / test-nightly (CPU Nightly (Clang), linux.4xlarge, --pre torch torchvision --index-url https://dow... / linux-job (gh) (similar failure)
  test/prototype/test_int4_opaque_tensor.py::TestInt4OpaqueTensor::test_module_path_float32_use_hqq_True

BROKEN TRUNK - The following jobs failed but was present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• Run 1xH100 Tests / test (H100, mt-l-x86iamx-22-225-h100, --pre torch torchvision mslk --index-url https://download.p... / linux-job (gh) (trunk failure)
  test/dtypes/test_affine_quantized_float.py::TestAffineQuantizedFloat8Compile::test_per_row_with_float32
• Run 1xL4 Tests / test (SM-89, linux.g6.4xlarge.experimental.nvidia.gpu, --pre torch --index-url https://download.p... / linux-job (gh) (trunk failure)
  test/dtypes/test_affine_quantized_float.py::TestAffineQuantizedFloat8Compile::test_per_row_with_float32
• Run Regression Tests / test-nightly (CPU Nightly, linux.4xlarge, --pre torch torchvision --index-url https://download.py... / linux-job (gh) (trunk failure)
  test/prototype/test_int4_opaque_tensor.py::TestInt4OpaqueTensor::test_module_path_float32_use_hqq_True
• Run Regression Tests / test-nightly (CUDA Nightly, linux.g5.12xlarge.nvidia.gpu, --pre torch torchvision --index-url htt... / linux-job (gh) (trunk failure)
  test/prototype/test_quantized_training.py::TestQuantizedTraining::test_int8_weight_only_training_compile_True_device_cuda

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[alexsamardzic]

This PR also contains a script to validate/benchmark the CuTeDSL 2D 32x1 dim1 quantization path against the existing CUDA path inside the wgrad workflow; the script is temporary and will be deleted when the torchao._C_mxfp8 extension removed.

[alexsamardzic]

Replaced by #4702.