Remove atlfast3 art tests from 21.9
Removing ATLFAST3 art tests from 21.9, where they are not needed (21.0 is the intended branch). Removing is also motivated by the ongoing reproducibility issues with these tests: ATLASSIM-5045.
Removing ATLFAST3 art tests from 21.9, where they are not needed (21.0 is the intended branch). Removing is also motivated by the ongoing reproducibility issues with these tests: ATLASSIM-5045.