function isDOMElement(Component) {
  return (typeof Component.type === 'string');
}
When an element's type is a string, it represents a DOM node with that tag name
https://facebook.github.io/react/blog/2015/12/18/react-components-elements-and-instances.html#dom-elements

@param {React.element} Component
@return {bool} Whether the component is a DOM Element