hash_match: add alternative matching method

[thomas-rasmussen]

The hash_match macro is very efficient if there are no or few inexact matching criteria. But as the number (and restrictiveness) of the inexact criteria increases, the approach of picking random controls from a pool potential controls becomes very inefficient. In some scenarios it might be more efficient to use a "cartesian product" approach. Maybe it is worth it to add an alternative matching approach to the macro for these cases? Implementing it should not be more difficult than adding some conditional logic switching between the hash-table and the alternative approach in the innermost part of the macro?

[thomas-rasmussen]

Nah, out of scope of the macro. Should be a separate macro concentrating on that specific approach to matching.