i do not have 737 experience, but
afaik the cfm56 are flat rated to ISA+15 , so on temperatures below that they do not temp out at rated power , pushing the levers to the stop ( beyond max permitted thrust) will result in asking them for a higher thrust than they are approved for and they may or may not go in overtemperature or/ and n2 overspeed -depending on the outside temperature and air density . on cooler days the may just work outside its envelope without bursting redlines.
i remember a similar procedure on the bae146 where a windshear called for immediate go around power- when at go around power aircraft still sinks and ground contact is likely firewall the thrust levers. after this the checklist calls for a landing as soon as practical and a hot section inspection.
the bae engines are very likely then to go in overtemp since they are only rated to ISA - at all temperatures and elevations above isa they are temperature limited.
it seems that the fuel stop position with levers full forward is adjusted high enough to force the engine beyond certification limits but low enough that the manufacturer "believes" it should not result in an immediate destruction and may be so a final and last option to intentionally overload and hurt the engines but save the aircraft.
its pretty the same like overtorquing a turboprop - it may make it, but nobody will quarantee it since its neither officially tested nor approved.
fadec controlled engines give us the peace of not fearing an overshoot but on the other hand they do not offer us such a "last option" .
cheers !