Fix converting boxed long to IntStringKey
Fix converting boxed long to IntStringKey

ref #700

peachpiecompiler/peachpie,iolevel/peachpie,iolevel/peachpie,peachpiecompiler/peachpie,peachpiecompiler/peachpie,iolevel/peachpie,iolevel/peachpie-concept,iolevel/peachpie-concept,iolevel/peachpie-concept