Support new pure HOC component

[bvaughn]

Follow up to PR facebook/react#13748

The following code:

function Counter({count}) {
  return <small>{count}</small>;
}
const PureCounterA = React.pure(({count}) => <small>{count}</small>);
const PureCounterB = React.pure(Counter);
const PureCounterC = React.pure(Counter);
PureCounterC.displayName = 'PureCounter';

Will now render the following in DevTools:

[bvaughn]

I'll revert this or iterate on it later if there are concerns.