Remove superfluous nqp::p6box_s
Remove superfluous nqp::p6box_s

These would probably be speshed/jitted away already, but this also
makes the code easier to read.

nbrown/rakudo,raydiak/rakudo,salortiz/rakudo,MasterDuke17/rakudo,lucasbuchala/rakudo,MasterDuke17/rakudo,usev6/rakudo,lucasbuchala/rakudo,sjn/rakudo,jonathanstowe/rakudo,usev6/rakudo,salortiz/rakudo,labster/rakudo,jonathanstowe/rakudo,tbrowder/rakudo,labster/rakudo,raydiak/rakudo,rakudo/rakudo,nbrown/rakudo,nbrown/rakudo,awwaiid/rakudo,jonathanstowe/rakudo,raydiak/rakudo,awwaiid/rakudo,tony-o/rakudo,salortiz/rakudo,labster/rakudo,softmoth/rakudo,salortiz/rakudo,lucasbuchala/rakudo,tony-o/rakudo,nbrown/rakudo,usev6/rakudo,lucasbuchala/rakudo,jonathanstowe/rakudo,tony-o/rakudo,MasterDuke17/rakudo,sjn/rakudo,labster/rakudo,sjn/rakudo,awwaiid/rakudo,sjn/rakudo,rakudo/rakudo,nbrown/rakudo,softmoth/rakudo,MasterDuke17/rakudo,MasterDuke17/rakudo,Gnouc/rakudo,tony-o/rakudo,softmoth/rakudo,labster/rakudo,salortiz/rakudo,softmoth/rakudo,MasterDuke17/rakudo,tony-o/rakudo,labster/rakudo,tbrowder/rakudo,tbrowder/rakudo,Gnouc/rakudo,sjn/rakudo,tbrowder/rakudo,nbrown/rakudo,usev6/rakudo,Gnouc/rakudo,salortiz/rakudo,Gnouc/rakudo,Gnouc/rakudo,usev6/rakudo,rakudo/rakudo,softmoth/rakudo,tony-o/rakudo,tbrowder/rakudo,Gnouc/rakudo,awwaiid/rakudo,jonathanstowe/rakudo,awwaiid/rakudo,rakudo/rakudo,rakudo/rakudo,raydiak/rakudo,tbrowder/rakudo,lucasbuchala/rakudo,rakudo/rakudo