Remove bogus coercion from Cool.substr.
Remove bogus coercion from Cool.substr.

Found by labster++.

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