[z2106] Let GetMapEntranceTrigger and GetGoBackTrigger work in a better defined order

Actually as this is still no total order (and it is basicly impossible to define a reasonable total order for areatrigger_teleport) it is not well defined, but probably good enough for all cases

(based on commit [12154] - 6bfcef0)

(based on commit [s1728] - 6e468ea)