MuonIdHelpers: Speed up validation for MDT.

The Min/Max calls used by the validation functions are expensive, since they scan over all ranges to find ones that match a given identifier.

Speed up by first combining the Min and Max calls into a single call, so we don't need to scan twice. (And for stations, combine eta/phi min/max into a single call.) And second, by indexing the ranges by station name, to reduce the number of ranges that we need to test.