Arm backend: Update parse_test_name script (#10902)

- Make TARGETS a list to preserve order.
- Replace edge_ops with a dict mapping test op names to edge op names,
e.g. op_name_map["split_tensor"] = "split_copy.Tensor"

Both changes are slightly less efficient compared to using sets, but
more convenient to use when handling the results.

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