Merged requested to merge adye/athena:21.3-tid-art7 into 21.3
- remove old test scripts that are no longer run
- rename test/*_art.sh to replace them, test/*.sh
- ML tests now generated from template
Note for reviewers, despite what the diff seems to show, this MR just renames the currently-running ART test scripts to replace the old ones. WIP flag removed for 21.3 now 21.9's MR's ART jobs run OK.