TruthUtils: Bugfixes and unit test update

AtlasPID.h Tweak definitions of a number of helper functions to avoid std::out_of_range errors when they are called for smaller pdg_id values. The tweaks should not alter the output of the functions for other pdg_id values as they are just a reordering of boolean statements.

At the same time the testPIDs unit test is updated to call all the functions which were previously missing. The reference file is updated to include the additional output. A follow-up MR will add a new set of pdg_id values to the test, so that there is at least one value where all the helper functions should return true.