Add Arm pass-utils and update passes (#5579)

Summary:
Add pass utils and update passes to make them more concise. Also fix a bug in ConvertSplitToSlicePass, where getitem nodes were not removed.

Change-Id: I9346abae93d58bfcbcf727c279c06e58bc94ba6b

Pull Request resolved: https://github.com/pytorch/executorch/pull/5579

Reviewed By: mergennachin

Differential Revision: D63638787

Pulled By: digantdesai

fbshipit-source-id: 1b744cec2b4da7bf801ae5e540e0c4193c4e1a3c