use non-relocatable values for gather sentinels
use non-relocatable values for gather sentinels

Presuming that Any.new.WHICH has a more stable address than [] does.
Anyway, passes the same tests, so appears to be no worse.

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