[cheats] Made &prefix:<defined> return a Bool.
[cheats] Made &prefix:<defined> return a Bool.

This fixes RT #81352.

paultcochrane/rakudo,ab5tract/rakudo,MasterDuke17/rakudo,ab5tract/rakudo,Gnouc/rakudo,tony-o/rakudo,retupmoca/rakudo,teodozjan/rakudo,laben/rakudo,ungrim97/rakudo,tony-o/deb-rakudodaily,ugexe/rakudo,ungrim97/rakudo,salortiz/rakudo,sergot/rakudo,ugexe/rakudo,dwarring/rakudo,tbrowder/rakudo,samcv/rakudo,skids/rakudo,LLFourn/rakudo,samcv/rakudo,Leont/rakudo,salortiz/rakudo,tbrowder/rakudo,cognominal/rakudo,pmurias/rakudo,paultcochrane/rakudo,azawawi/rakudo,MasterDuke17/rakudo,ab5tract/rakudo,tony-o/rakudo,cygx/rakudo,cognominal/rakudo,softmoth/rakudo,jonathanstowe/rakudo,salortiz/rakudo,niner/rakudo,rakudo/rakudo,sjn/rakudo,labster/rakudo,zostay/rakudo,zostay/rakudo,laben/rakudo,samcv/rakudo,retupmoca/rakudo,tbrowder/rakudo,dankogai/rakudo,awwaiid/rakudo,jonathanstowe/rakudo,salortiz/rakudo,tony-o/rakudo,sjn/rakudo,azawawi/rakudo,rjbs/rakudo,niner/rakudo,ugexe/rakudo,skids/rakudo,b2gills/rakudo,softmoth/rakudo,paultcochrane/rakudo,labster/rakudo,tony-o/deb-rakudodaily,jonathanstowe/rakudo,raydiak/rakudo,ungrim97/rakudo,sergot/rakudo,MasterDuke17/rakudo,softmoth/rakudo,lucasbuchala/rakudo,nunorc/rakudo,cognominal/rakudo,Gnouc/rakudo,dankogai/rakudo,labster/rakudo,tbrowder/rakudo,usev6/rakudo,zhuomingliang/rakudo,zhuomingliang/rakudo,nbrown/rakudo,sjn/rakudo,pmurias/rakudo,sergot/rakudo,LLFourn/rakudo,retupmoca/rakudo,Gnouc/rakudo,dankogai/rakudo,softmoth/rakudo,tony-o/deb-rakudodaily,teodozjan/rakudo,salortiz/rakudo,sergot/rakudo,ab5tract/rakudo,paultcochrane/rakudo,rjbs/rakudo,retupmoca/rakudo,laben/rakudo,dwarring/rakudo,ugexe/rakudo,zostay/rakudo,nbrown/rakudo,Leont/rakudo,MasterDuke17/rakudo,azawawi/rakudo,awwaiid/rakudo,samcv/rakudo,b2gills/rakudo,niner/rakudo,dwarring/rakudo,jonathanstowe/rakudo,nunorc/rakudo,ab5tract/rakudo,niner/rakudo,cygx/rakudo,tony-o/deb-rakudodaily,Leont/rakudo,ungrim97/rakudo,LLFourn/rakudo,cygx/rakudo,azawawi/rakudo,samcv/rakudo,rakudo/rakudo,ugexe/rakudo,pmurias/rakudo,teodozjan/rakudo,dankogai/rakudo,tony-o/deb-rakudodaily,cygx/rakudo,nbrown/rakudo,Gnouc/rakudo,tony-o/rakudo,usev6/rakudo,b2gills/rakudo,Gnouc/rakudo,raydiak/rakudo,Leont/rakudo,tony-o/rakudo,usev6/rakudo,rakudo/rakudo,nunorc/rakudo,labster/rakudo,LLFourn/rakudo,cygx/rakudo,LLFourn/rakudo,rakudo/rakudo,tony-o/deb-rakudodaily,teodozjan/rakudo,labster/rakudo,lucasbuchala/rakudo,zhuomingliang/rakudo,tbrowder/rakudo,skids/rakudo,rjbs/rakudo,zhuomingliang/rakudo,dankogai/rakudo,labster/rakudo,nbrown/rakudo,skids/rakudo,sjn/rakudo,awwaiid/rakudo,awwaiid/rakudo,lucasbuchala/rakudo,ungrim97/rakudo,awwaiid/rakudo,zostay/rakudo,nunorc/rakudo,tony-o/deb-rakudodaily,sjn/rakudo,lucasbuchala/rakudo,azawawi/rakudo,rakudo/rakudo,usev6/rakudo,softmoth/rakudo,MasterDuke17/rakudo,jonathanstowe/rakudo,raydiak/rakudo,usev6/rakudo,skids/rakudo,nbrown/rakudo,Gnouc/rakudo,paultcochrane/rakudo,tbrowder/rakudo,cognominal/rakudo,nbrown/rakudo,MasterDuke17/rakudo,b2gills/rakudo,tony-o/rakudo,cognominal/rakudo,b2gills/rakudo,laben/rakudo,pmurias/rakudo,salortiz/rakudo,raydiak/rakudo,rakudo/rakudo,lucasbuchala/rakudo,dwarring/rakudo