Quantize moveaxis/movedim so they delegate to Ethos-U (#20314)

[apullin]

Summary:

The ARM PT2 quantizer's pass-through shared-qspec set in quantization_annotator.py
(_one_to_one_shared_input_qspec) covers permute/permute_copy/transpose/view/squeeze
etc., but omits aten.moveaxis/aten.movedim. A model that uses torch.moveaxis
therefore leaves those ops unquantized: the quantizer brackets each one with
dequantize -> moveaxis(float) -> quantize.

On lowering, moveaxis decomposes to a float permute_copy. The Ethos-U55
operator-support check (operator_support/ethos_u55_support.py) only delegates
permute_copy for int8/int16/int32, so it rejects the float one. Each rejected
permute is stranded on the host, splitting the model into many delegated
partitions (one NPU island per permute), which bloats the .pte with per-partition
delegate overhead and host round-trips.

Add aten.moveaxis.int / aten.movedim.int to _one_to_one_shared_input_qspec
(guarded with getattr for torch-build variance, mirroring the existing
transpose.Dimname handling) so they share the input quantization spec exactly like
transpose/permute. They then stay int8, decompose to int8 permute_copy, and
delegate to the NPU -- eliminating the host float islands.

Impact: a quantized example ensemble (ConvNeXt-style blocks that
use torch.moveaxis) that previously lowered into 9 Ethos-U55 partitions now lowers
into a single delegate, with zero host permutes and ~24% smaller .pte, with no
model changes. Generalizes to any moveaxis/movedim-using model on the Ethos-U
backend.

Reviewed By: JakeStevens

Differential Revision: D108478011

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

[pytorch-bot]

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❌ 5 New Failures, 7 Unrelated Failures

As of commit 5d80055 with merge base 1b726b2 ():

NEW FAILURES - The following jobs have failed:

• pull / test-arm-backend-no-driver (test_pytest_ops_tosa) / linux-job (gh)
  RuntimeError: Command docker exec -t 635496a893356c46d08bb1f28b7a14344087059553c12ad8e1c6f13e8bbc61d9 /exec failed with exit code 1
• pull / test-static-llama-qnn-linux (stories_110m) / linux-job (gh)
  RuntimeError: Command docker exec -t 5d8336e6e559018787d587d6712788e0aba69f39bf3a334df115a111fab706a1 /exec failed with exit code 92
• pull / unittest-editable / linux / linux-job (gh)
  RuntimeError: Command docker exec -t 59f30353fdec194f985bd9e8c439cdeb0df798bc6ab6358ee86a26e5eded865f /exec failed with exit code 1
• trunk / test-arm-backend-vkml (test_pytest_ops_vkml) / linux-job (gh)
  RuntimeError: Command docker exec -t 464c49403e7030de4cf329410bb5ab65c3b7c27822b2aa3b4e5451213a2733c2 /exec failed with exit code 1
• trunk / test-qnn-optimum-model (fp32, distilbert) / linux-job (gh)
  RuntimeError: Command docker exec -t 6667785cd5b25af0a4556940e45458862cdcdc9168f87d19fa26a85e675b708c /exec failed with exit code 92

FLAKY - The following jobs failed but were likely due to flakiness present on trunk:

• pull / unittest / linux / linux-job (gh) (detected as infra flaky with no log or failing log classifier)
• pull / unittest / macos / macos-job (gh) (detected as infra flaky with no log or failing log classifier)
• trunk / unittest-release / linux / linux-job (gh) (detected as infra flaky with no log or failing log classifier)

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

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

• pull / test-llama-runner-qnn-linux (fp32, qnn_16a16w, qnn) / linux-job (gh) (trunk failure)
• 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
• trunk / test-llama-runner-qnn-linux (fp32, qnn_16a16w, qnn) / linux-job (gh) (trunk failure)
• trunk / unittest-release / 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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