We used to throw if event listener is not a function in Stack:

```js
ReactDOM.render(
  <h1 onClick={{}}>Hello World!</h1>,
  document.getElementById('container')
);
```

<img width="565" alt="screen shot 2017-08-08 at 3 41 08 pm" src="https://user-images.githubusercontent.com/810438/29077502-2646412e-7c50-11e7-8c99-3b7f6c0a2589.png">

Fiber silently ignores this.

I think we should throw. This would let us add support for objects (e.g. for passive listener configuration) if we want to in a minor rather than a major.
var container = document.createElement('div');
      ReactDOM.render(
        <my-component
          children={['foo']}
          suppressContentEditableWarning={true}
        />,
        container,
      );
      expect(container.firstChild.hasAttribute('children')).toBe(false);
      expect(
        container.firstChild.hasAttribute('suppressContentEditableWarning'),
      ).toBe(false);
      ReactDOM.render(
        <my-component
          children={['bar']}
          suppressContentEditableWarning={false}
        />,
        container,
      );
      expect(container.firstChild.hasAttribute('children')).toBe(false);
      expect(
        container.firstChild.hasAttribute('suppressContentEditableWarning'),
      ).toBe(false);
    });
    it('should skip dangerouslySetInnerHTML on web components', () => {
      var container = document.createElement('div');
      ReactDOM.render(
        <my-component dangerouslySetInnerHTML={{__html: 'hi'}} />,
        container,
      );