21.9 step 3 muons test
Adding a new ART test running "Step 3.0" style ITK geometry, 100 GeV muons, as a first example. More tests will be populated for this layout once the configuration is seen to work.
Also updating the PixelRDOAnalysis to accommodate the increased number of layers in these layouts to avoid crashes with out-of-range array access. As discussed in !24656 (merged):
future MR should probably update the tools to generally remove this dependence on hardcoded geometry details, and the reliance on C-style histogram arrays without bounds checking.
The methods decided and used there should eventually also be propagated here.