Arm backend: Add Qwen3 VL language model MXFP8 test

[tom-arm]

• Add an E2E TOSA test for the Qwen3 VL language model with linear layers converted to MXFP8.

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

[pytorch-bot]

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❌ You can merge normally! (3 Unrelated Failures), 1 Unclassified Failure

As of commit 0728a47 with merge base a2438e4 ():

UNCLASSIFIED FAILURE - DrCI could not classify the following job because the workflow did not run on the merge base. The failure may be pre-existing on trunk or introduced by this PR:

• trunk / test-models-macos-coreml (ic4) / macos-job (gh) (this job did not run on the merge base, so DrCI cannot tell whether the failure is pre-existing)
  RuntimeError: Command bash /Users/ec2-user/runner/_work/_temp/exec_script failed with exit code 1

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

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

• pull / unittest / windows / windows-job (gh) (trunk failure)
  Process completed with exit code 2.
• pull / unittest-editable / windows / windows-job (gh) (trunk failure)
  Process completed with exit code 2.
• trunk / unittest-release / windows / windows-job (gh) (trunk failure)
  Process completed with exit code 2.

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[Copilot]

Pull request overview

Adds an end-to-end Arm TOSA test to validate MXFP8 (FP8 e4m3) conversion for the Qwen3-VL TextModel path, ensuring BF16 + MXFP lowering and accuracy checks work together for this model family.

Changes:

• Introduces an MXFP8 + BF16 TOSA pipeline test for TextModelWrapper using MXFPTosaPipelineFP.
• Adds a Linear-module filter and a post-export op-count assertion to verify all nn.Linear layers are rewritten to torch.ops.tosa_mxfp.linear.default.

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[tom-arm]

/easycla