Updating the ART test configuration to match 21.0 will switch of
these ART tests for the 21.1 branch.


Former-commit-id: d0f209c9a75a80c557467b268a468b96f9ba6a41

Former-commit-id: c66b30ccbd72db74c7b5c0d80a94adfe8ce3ea09

Splitting these transform commands up into multiple lines makes it easier to
diff the commands when configuration is changed in the future.


Former-commit-id: 6b75d7a90c147bc82452a62c43a8989a6447ee25

ART Tests have been updated to only run for certain branch/project
combinations and have also been updated to save output root files
where useful.


Former-commit-id: 5899b8d6743cd4545a78fcb8adbba48665f282ea

Former-commit-id: 25df8d46b0a779bc83efd67c52fac6fa4231a242

Initially adding jobs for AtlasG4_tf.py (single-threaded) and Sim_tf.py FullG4 (single-threaded).
See discussion in !6876.


Former-commit-id: 61b3ce24caf0540eb207c4fff4eb2acf6d70c7f7