NXP backend: Add option to use the new Neutron flow.

[MartinPavella]

Summary

The new Neutron C flow is based on MLIR, and it provides improved support for many operators. This PR adds to option to use it.

Test plan

Unit test provided.

cc @robert-kalmar @JakeStevens @digantdesai

[pytorch-bot]

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❌ 1 New Failure, 1 Cancelled Job, 1 Pending, 2 Unrelated Failures

As of commit 7acffcd with merge base c48ea12 ():

NEW FAILURE - The following job has failed:

• Test CoreML Backend / test-coreml / test-backend-macos (coreml, operators) / macos-job (gh)
  RuntimeError: Command bash /Users/ec2-user/runner/_work/_temp/exec_script failed with exit code 1

CANCELLED JOB - The following job was cancelled. Please retry:

• pull / unittest-buck / macos / macos-job (gh)
  ##[error]The operation was canceled.

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

• pull / unittest / windows / windows-job (gh) (matched win rule in flaky-rules.json)
  ##[error]The operation was canceled.

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

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

• pull / unittest-editable / windows / windows-job (gh) (trunk failure)
  ##[error]The operation was canceled.

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[MartinPavella]

@novak-vaclav @roman-janik-nxp @StrycekSimon feel free to base the enablement of new operators on this PR.
It will not be merged until we migrate to Neutron SDK 3.1.0. For now, new additions based on this SDK will be stored as draft PRs.