MLX delegate (part 1)

[metascroy]

Takes changes from #16718, but strips all ops (except addmm) and examples.

Part2 will add back ops, and part 3 will add back examples.

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/17803

• 📄 Preview Python docs built from this PR

Note: Links to docs will display an error until the docs builds have been completed.

❌ 2 New Failures, 3 Cancelled Jobs, 4 Unrelated Failures

As of commit 540ad17 with merge base 3ae1003 ():

NEW FAILURES - The following jobs have failed:

• pull / test-samsung-models-linux / linux-job (gh)
  test_inception_v4_fp16
• pull / unittest / macos / macos-job (gh)
  The process '/usr/bin/git' failed with exit code 128

CANCELLED JOBS - The following jobs were cancelled. Please retry:

• Test ARM Backend / test-arm / test-backend-linux (arm_tosa_fp, models) / linux-job (gh)
  ##[error]The operation was canceled.
• Test ARM Backend / test-arm / test-backend-linux (arm_vgf_fp, models) / linux-job (gh)
  ##[error]The operation was canceled.
• trunk / test-models-macos-coreml (ic3) / macos-job (gh)
  ##[error]The operation was canceled.

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-editable / macos / macos-job (gh) (trunk failure)
  AttributeError: '_OpNamespace' 'mkldnn' object has no attribute '_is_mkldnn_acl_supported'
• Test CUDA Windows Export and E2E / test-model-cuda-windows-e2e (mistralai, Voxtral-Mini-3B-2507, non-quantized) / windows-job (gh) (trunk failure)
  Process completed with exit code 1.
• Test CUDA Windows Export and E2E / test-model-cuda-windows-e2e (mistralai, Voxtral-Mini-3B-2507, quantized-int4-weight-only) / windows-job (gh) (trunk failure)
  Process completed with exit code 1.
• trunk / unittest-release / macos / macos-job (gh) (trunk failure)
  AttributeError: '_OpNamespace' 'mkldnn' object has no attribute '_is_mkldnn_acl_supported'

This comment was automatically generated by Dr. CI and updates every 15 minutes.

[github-actions]

This PR needs a release notes: label

If your change should be included in the release notes (i.e. would users of this library care about this change?), please use a label starting with release notes:. This helps us keep track and include your important work in the next release notes.

To add a label, you can comment to pytorchbot, for example
@pytorchbot label "release notes: none"

For more information, see
https://github.com/pytorch/pytorch/wiki/PyTorch-AutoLabel-Bot#why-categorize-for-release-notes-and-how-does-it-work.

[meta-codesync]

@metascroy has imported this pull request. If you are a Meta employee, you can view this in D94997043.