Arm backend: test_pipeline improvements (#8644)

- Add OpNotSupportedPipeline for checking that ops are not delegated
  properly.
- Make use_to_edge_transform_and_lower default to true since this is the
  recommended API.
- Rename TestPassPipeline -> PassPipeline to avoid warnings in pytest
  log, and make exir_ops optional as its not used then.
- Allow to add the first non unique stage to a pipeline w/o suffix
  (E.g. run_method_and_compare_outputs will rarely be used twice even
  though it is theoretically possible, so we don't want to refer to it
  as run_method_and_compare_outputs.0 if not necessary).
- Add custom_path option to all pipelines for easily dumping artifacts.
- Typing and documentation fixes.

Signed-off-by: Adrian Lundell <adrian.lundell@arm.com>