Qualcomm AI Engine Direct - Adding QNN backend support for _cdist_forward core ATen op

[qti-horodnic]

Summary

Added support for the _cdist_forward core ATen op using the existing implementation for CDist. Note this is an internal ATen variant of torch.cdist that torch.export produces, so just added the target to the existing pass for CDist and other small additions to make sure the pass is registered in the correct pipelines.

Test plan

python backends/qualcomm/tests/test_qnn_delegate.py -k TestQNNFloatingPointOperator.test_qnn_backend_cdist_forward --model SM8750 --host aisw-vm15-labsd --device 545ee4aa --build_folder build-android

python backends/qualcomm/tests/test_qnn_delegate.py -k TestQNNQuantizedOperator.test_qnn_backend_cdist_forward --model SM8750 --host aisw-vm15-labsd --device 545ee4aa --build_folder build-android

cc @cccclai @cbilgin @abhinaykukkadapu

[pytorch-bot]

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🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/20195

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❌ 1 Awaiting Approval, 1 New Failure, 1 Unrelated Failure

As of commit f725c7c with merge base 4519036 ():

AWAITING APPROVAL - The following workflow needs approval before CI can run:

• periodic (gh)

NEW FAILURE - The following job has failed:

• Build Presets / apple (ios-simulator) / build (gh)
  The process '/opt/homebrew/bin/git' failed with exit code 128

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

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

• pull / android / build-android (gh) (trunk failure)
  Process completed with exit code 1.

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[qti-horodnic]

@pytorchbot label "release notes: qualcomm"