NXP backend: Remove optimization in keep_one_empty_buffer.py

[roman-janik-nxp]

Summary

Remove unnecessary optimization in keep_one_empty_buffer.py in IR optimizer.

Test plan

All tests where a subgraph is delegated to Neutron.

cc @digantdesai @JakeStevens @robert-kalmar @Pop-Korn

[pytorch-bot]

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❌ 1 New Failure, 4 Unrelated Failures

As of commit bbd31f6 with merge base ea4a7fa ():

NEW FAILURE - The following job has failed:

• pull / unittest-nxp-neutron / linux-job (gh)
  RuntimeError: Command docker exec -t a64db95181ab8ccff105b77f66aec891f55b2a3e5745ea5af9ca348600e3936b /exec 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 / linux / linux-job (gh) (trunk failure)
  examples/models/llama/tests/test_ring_attention.py::TestRingAttention::test_single_token_processing_quantized
• 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 / linux / linux-job (gh) (trunk failure)
  examples/models/llama/tests/test_ring_attention.py::TestRingAttention::test_single_token_processing_quantized
• 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

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[roman-janik-nxp]

@pytorchbot label "module: nxp" "release notes: nxp"

[MartinPavella]

LGTM

[robert-kalmar]

Please fix the failures.

[robert-kalmar]

Moving to draft stage, as this is not really an optimization, but a postprocessing phase to generate a valid tflite model representation. This pass must stay, but perhaps to be moved outside of the backends/nxp/backend/ir/tflite_optimizer/optimizations package

[roman-janik-nxp]

Closing now as this code needs to be moved instead of removed. New PR will be created.