Make .minpairs/.maxpairs about 6% faster
Make .minpairs/.maxpairs about 6% faster

Well, really depends on size, hash order and values, but at least
we're not doing an unnecessary "next" anymore.  Benchmark was on:
<a b b c c c d d d d>.Bag .

Also micro-optimize QuantHash.fmt

raydiak/rakudo,raydiak/rakudo,nbrown/rakudo,Gnouc/rakudo,tony-o/rakudo,tbrowder/rakudo,MasterDuke17/rakudo,softmoth/rakudo,salortiz/rakudo,usev6/rakudo,sjn/rakudo,raydiak/rakudo,nbrown/rakudo,azawawi/rakudo,samcv/rakudo,usev6/rakudo,Gnouc/rakudo,Gnouc/rakudo,samcv/rakudo,salortiz/rakudo,tony-o/rakudo,lucasbuchala/rakudo,tbrowder/rakudo,samcv/rakudo,usev6/rakudo,tbrowder/rakudo,nbrown/rakudo,b2gills/rakudo,awwaiid/rakudo,Gnouc/rakudo,jonathanstowe/rakudo,jonathanstowe/rakudo,tbrowder/rakudo,softmoth/rakudo,zostay/rakudo,azawawi/rakudo,nbrown/rakudo,sjn/rakudo,softmoth/rakudo,b2gills/rakudo,azawawi/rakudo,tbrowder/rakudo,zostay/rakudo,sjn/rakudo,zostay/rakudo,labster/rakudo,rakudo/rakudo,MasterDuke17/rakudo,Gnouc/rakudo,samcv/rakudo,lucasbuchala/rakudo,salortiz/rakudo,labster/rakudo,softmoth/rakudo,zostay/rakudo,jonathanstowe/rakudo,labster/rakudo,usev6/rakudo,MasterDuke17/rakudo,azawawi/rakudo,rakudo/rakudo,softmoth/rakudo,b2gills/rakudo,tbrowder/rakudo,jonathanstowe/rakudo,nbrown/rakudo,sjn/rakudo,awwaiid/rakudo,tony-o/rakudo,labster/rakudo,lucasbuchala/rakudo,rakudo/rakudo,rakudo/rakudo,rakudo/rakudo,awwaiid/rakudo,b2gills/rakudo,lucasbuchala/rakudo,Gnouc/rakudo,b2gills/rakudo,tony-o/rakudo,nbrown/rakudo,lucasbuchala/rakudo,sjn/rakudo,tony-o/rakudo,jonathanstowe/rakudo,MasterDuke17/rakudo,tony-o/rakudo,awwaiid/rakudo,MasterDuke17/rakudo,labster/rakudo,rakudo/rakudo,salortiz/rakudo,raydiak/rakudo,usev6/rakudo,salortiz/rakudo,salortiz/rakudo,samcv/rakudo,azawawi/rakudo,MasterDuke17/rakudo,awwaiid/rakudo,labster/rakudo