Fix variability in Logic test (some tests don't yield the same results on all platforms)

[lucteo]

Please see the following tests:
- Logic: parents example, with recursive calls / All males KNOWN-PROBLEM
- Logic: parents example, with recursive calls / All females KNOWN-PROBLEM
- Logic: parents example, with recursive calls / All fathers KNOWN-PROBLEM
- Logic: parents example, with recursive calls / All mothers KNOWN-PROBLEM
- Logic: solar system example / All planets KNOWN-PROBLEM
- Logic: solar system example / All satellites KNOWN-PROBLEM
- Logic: parsing Prolog code / Injecting Prolog - solar system KNOWN-PROBLEM
- Logic: parsing Prolog code / Injecting Prolog - parents KNOWN-PROBLEM