Make the benchmark a little more precise
Make the benchmark a little more precise

We special-case identical vnode trees, so it's better that we test both
identical and rebuilt trees when benchmarking rendering.

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