Revert "Arm backend: Add 16A8W linear ops support and test (#13754)"

[lucylq]

This reverts commit f8156fb.

Summary

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Test plan

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⏳ 15 Pending, 1 Unrelated Failure

As of commit ad98b07 with merge base 19a54bc ():

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

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

• pull / unittest-nxp-neutron / linux-job (gh) (trunk failure)
  test_split_group_convolution__applied_by_default

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