[ET-VK][ez] Make q8ta_conv2d use 4C1W layout

[SS-JIA]

Stack from ghstack (oldest at bottom):

• [ET-VK][profiling] Add additional profiling blocks #17394
• [ET-VK][qconv2d][ez] Don't use im2col path for general convs #17393
• [ET-VK] Add nchw_to_int8x4_buffer shader for prepacking int8 staging data #17392
• [ET-VK] Layout-flexible impl of quantized binary #17391
• -> [ET-VK][ez] Make q8ta_conv2d use 4C1W layout #17390
• [ET-VK][ez] Add AOT support for PackedInt8_4C1W dtype #17389
• [ET-VK] Migrate to use new q8ta_conv2d ops #17388
• [ET-VK][qconv] Dynamically select between im2col path and general path #17387
• [ET-VK][qconv][ez] Make q8ta_im2col shader support stride_w != 1 #17386
• Back out "[Diff Train][pytorch/executorch] Apply fixup patch to fbsource" #17399

This changes the q8ta_conv2d and q8ta_conv2d_dw operators' input layout from PackedInt8_4W4C to PackedInt8_4C1W in the op registry. The 4C1W layout aligns with the natural output format of channel-packed convolutions, avoiding unnecessary layout conversions between consecutive conv layers.

Also adds explicit outputs_storage declarations (PACKED_INT8_CHANNELS_PACKED_BUFFER) to both the PW and general q8ta_conv2d op registrations, ensuring the layout propagation pass can correctly determine output layouts.

Differential Revision: D93000165

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/17390

• 📄 Preview Python docs built from this PR

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

❌ 5 New Failures, 1 Unrelated Failure

As of commit 03aec14 with merge base 964c565 ():

NEW FAILURES - The following jobs have failed:

• Test CUDA Builds / export-model-cuda-artifact (google, gemma-3-4b-it, quantized-int4-tile-packed) / linux-job (gh)
  RuntimeError: Command docker exec -t 9e4008bd61680d3ec45e28d7104127313fc94a507634b5b320c0e1e483156027 /exec failed with exit code 1
• Test CUDA Builds / export-model-cuda-artifact (nvidia, parakeet-tdt, quantized-int4-weight-only) / linux-job (gh)
  RuntimeError: Command docker exec -t 3c872cc7cd488090e1b5bea4a13633bf19fbec6aac7a863649e4d75d319dac91 /exec failed with exit code 1
• Test CUDA Builds / export-model-cuda-artifact (openai, whisper-small, non-quantized) / linux-job (gh)
  RuntimeError: Command docker exec -t 37f2f020dfd1ad0f42e00b80ee2489e51581827f20ab5223dcf7e8b2f2f86a55 /exec failed with exit code 1
• Test CUDA Builds / test-models-cuda (mv2) / linux-job (gh)
  RuntimeError: Command docker exec -t 072623d3ae0b696b96d34989430aa457fcfb2c94815185f74a7d41a968a6a143 /exec failed with exit code 1
• Test CUDA Builds / test-models-cuda (sdpa) / linux-job (gh)
  RuntimeError: Command docker exec -t ee667ae77adc7320f5bcda1cffe3381cd6aa8c2a76e1ffcbd4ec34a438b759a9 /exec failed with exit code 1

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

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

• pull / test-samsung-models-linux / linux-job (gh) (trunk failure)
  ##[error]The operation was canceled.

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.