Exclude arti-bench from coverage.

This program is itself for testing; we don't strongly care how much coverage it has on its own.

(Please only merge if you think this is a good idea.)

requested review from @eta

assigned to @nickm

(Please only merge if you think this is a good idea.)

Yeah, I think it is!

approved this merge request

enabled an automatic merge when the pipeline for 3f85e69a succeeds

merged

mentioned in commit 12045cb4

mentioned in merge request !221 (merged)

mentioned in commit 5b6b0d6a