Ability to run single-slices, migrate single-slice tests to a single jO

Stewart Martin-Haugh requested to merge smh/athena:select_slices_new into master

Replaces !22216 (closed)

Eventually this should interact with a mechanism in TriggerMenuMT to enable only specific signatures and division of the menu by slice, as we had in Run 2 (see ATR-19601).



Merge request reports