Specify ignore lists via full path

[surovic]

Maybe this shouldn't be prefixed by ABI_PATH in a future version. If you specify an ignore list, you could just as well specify the full path to it.
It is the same behavior as we've had for the dfsan abi-list so I don't think you need to change here, but might be a detail to add as an enhancement for future work.

Originally posted by @hbrodin in #6473 (comment)