Always coerce first argument to &round to Numeric.
Always coerce first argument to &round to Numeric.

Fixes rakudo/rakudo#1745.

tony-o/rakudo,salortiz/rakudo,tbrowder/rakudo,tony-o/rakudo,softmoth/rakudo,salortiz/rakudo,nbrown/rakudo,salortiz/rakudo,tony-o/rakudo,labster/rakudo,softmoth/rakudo,softmoth/rakudo,nbrown/rakudo,labster/rakudo,tbrowder/rakudo,tbrowder/rakudo,Gnouc/rakudo,Gnouc/rakudo,MasterDuke17/rakudo,MasterDuke17/rakudo,salortiz/rakudo,labster/rakudo,rakudo/rakudo,tony-o/rakudo,Gnouc/rakudo,Gnouc/rakudo,rakudo/rakudo,nbrown/rakudo,MasterDuke17/rakudo,nbrown/rakudo,nbrown/rakudo,rakudo/rakudo,rakudo/rakudo,labster/rakudo,MasterDuke17/rakudo,rakudo/rakudo,tbrowder/rakudo,MasterDuke17/rakudo,salortiz/rakudo,labster/rakudo,labster/rakudo,softmoth/rakudo,MasterDuke17/rakudo,rakudo/rakudo,nbrown/rakudo,tony-o/rakudo,salortiz/rakudo,Gnouc/rakudo,softmoth/rakudo,Gnouc/rakudo,tbrowder/rakudo,tbrowder/rakudo,tony-o/rakudo