21.2 - Fix logic in precision layer counting for forward muons
@jojungge and @nkoehler noticed that the current logic in the counting of precision layers for forward muons might allow double counting of the middle and outer layers in particular circumstances with overlap between small and large sectors. This is now fixed.
The fix has a very small impact and only affects stand-alone and silicon-associated forward muons in the region |eta| > 2.5 entering the Loose and Medium working points.
It was useful to extend the MuonSelectorToolsTester slightly to keep track of changes in different eta regions, so this is also included in the merge request.