Policy integrity test refactor via permutations

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• commit message follows commit guidelines

This refactors the policy test to do a full set of permutations of various possible configurations. It is rather extensive and thus likely not best to put into fixtures. Along the way a few bugs were found, due to refactors that did not have test coverage such as the new package_json_reader abstraction. These permutations should cover all the existing 24 variants in the original file and much more (at time of writing it hits 1300 permutations). I have put enough info in the debuglog('test') to recreate the permutation if you are trying to track down what broke, but it isn't ideal.