fix infinite recursion while type-annotating MayBeUndefined<T>
fix infinite recursion while type-annotating MayBeUndefined<T>

jsx/JSX,mattn/JSX,dj31416/JSX,jsx/JSX,jsx/JSX,dj31416/JSX,mattn/JSX,dj31416/JSX,jsx/JSX,dj31416/JSX,dj31416/JSX,jsx/JSX