[performance testing] add classes in some selectors for the attrs test
[performance testing] add classes in some selectors for the attrs test

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