Given the following test case

``` jsx
function TestCmp() {
  return <span>{NaN}</span>;
}

ReactDOM.render(<TestCmp />, document.getElementById('app'));
```

Produces the following warning:

```
Warning: Component's children should not be mutated.
    in span (created by TestCmp)
    in TestCmp (created by Unknown)
```

This is probably caused by [this mutation check](https://github.com/facebook/react/blob/328fc75bc910032ff37dc9d93429fb14b476bd0d/src/renderers/shared/hooks/ReactChildrenMutationWarningHook.js#L34), which was introduced in 15.3.0, but it doesn't work for NaN, because NaN != NaN

render() {
          return <span><NestedComponent /></span>;
        }
      }
      var response = ReactServerRendering.renderToStaticMarkup(
        <TestComponent />
      );
      expect(response).toBe('<span><div>inner text</div></span>');
    });
    it('should not put checksum and React ID on text components', () => {
      class TestComponent extends React.Component {
        render() {
          return <span>{'hello'} {'world'}</span>;
        }
      }
      var response = ReactServerRendering.renderToStaticMarkup(
        <TestComponent />
      );
      expect(response).toBe('<span>hello world</span>');
    });
    it('should not register event listeners', () => {
      var EventPluginHub = require('EventPluginHub');
      var cb = jest.fn();
      ReactServerRendering.renderToStaticMarkup(
        <span onClick={cb}>hello world</span>
      );
      expect(EventPluginHub.__getListenerBank()).toEqual({});
    });
    it('should only execute certain lifecycle methods', () => {
      function runTest() {