Fix a few CX creation cases and don't give a null to p6box_s
Fix a few CX creation cases and don't give a null to p6box_s

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