Arm backend: Add Qwen3 VL FP32 MXFP8 layer tests

[YufengShi-dudu]

Add TOSA MXFP8 coverage for Qwen3 VL text attention, MLP, and decoder layer wrappers. Keep the tests in FP32 while converting linear layers to MXFP through the MXFP pipeline.

Change-Id: Ib94bfdc114031a7558d42ea9e347142d721f7403

cc @digantdesai @freddan80 @per @zingo @oscarandersson8218 @mansnils @Sebastian-Larsson @robell @rascani

[pytorch-bot]

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• [ROCm] MI350 CI jobs will have longer queue times due to CI migration

❌ 3 New Failures, 1 Pending, 6 Unrelated Failures

As of commit 150b84f with merge base 252f57c ():

NEW FAILURES - The following jobs have failed:

• pull / unittest / linux / linux-job (gh)
  RuntimeError: Command docker exec -t 3d1d8414dbdb778be75ff53f4c476dd202c6cb8a54791a90c896def2ccca1561 /exec failed with exit code 1
• pull / unittest-editable / linux / linux-job (gh)
  RuntimeError: Command docker exec -t dedb37608a8f648aecdc67f4468fa5a28df871c7a9a4de7b1c2e184699aea381 /exec failed with exit code 1
• trunk / unittest-release / linux / linux-job (gh)
  RuntimeError: Command docker exec -t 1d9d17081bdadbdb11c7cdf170b2f4b10a2e7fe579ac142c4b9aa985ff884192 /exec failed with exit code 1

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

• pull / test-qnn-testsuite-linux / test-backend-linux (qnn, models) / linux-job (gh) (detected as infra flaky with no log or failing log classifier)

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

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

• pull / test-llama-runner-qnn-linux (fp32, qnn_16a16w, qnn) / linux-job (gh) (trunk failure)
• pull / unittest / macos / macos-job (gh) (trunk failure)
  RuntimeError: Command bash /Users/ec2-user/runner/_work/_temp/exec_script failed with exit code 1
• pull / unittest-editable / macos / macos-job (gh) (trunk failure)
  RuntimeError: Command bash /Users/ec2-user/runner/_work/_temp/exec_script failed with exit code 1
• trunk / test-llama-runner-qnn-linux (fp32, qnn_16a16w, qnn) / linux-job (gh) (trunk failure)
• trunk / unittest-release / macos / macos-job (gh) (trunk failure)
  RuntimeError: Command bash /Users/ec2-user/runner/_work/_temp/exec_script failed with exit code 1

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