[benchmark] add consecutive nullish values to the attrs test
[benchmark] add consecutive nullish values to the attrs test

pygy/mithril.js,lhorie/mithril.js,barneycarroll/mithril.js,MithrilJS/mithril.js,MithrilJS/mithril.js,lhorie/mithril.js,impinball/mithril.js,pygy/mithril.js,barneycarroll/mithril.js,impinball/mithril.js