Observed this on react@16.0.0-beta.5

```js
import React from 'react';
import { renderToString } from 'react-dom/server';

const B = () => 'b';

console.log(renderToString(<div>{'a'}<B />{'c'}</div>));
```

This renders as `<div data-reactroot="">a<!-- -->bc</div>`. If you try to hydrate this you'll get the error: Text content did not match. Server: "bc" Client: "b".
render() {
          return <div>{this.context.text}</div>;
        }
      }
      ClassChildWithContext.contextTypes = {text: PropTypes.string};
      const e = await render(
        <PurpleContext><ClassChildWithContext /></PurpleContext>,
      );
      expect(e.textContent).toBe('purple');
    });
    itRenders('stateless child with context', async render => {
      function StatelessChildWithContext(props, context) {
        return <div>{context.text}</div>;
      }
      StatelessChildWithContext.contextTypes = {text: PropTypes.string};
      const e = await render(
        <PurpleContext><StatelessChildWithContext /></PurpleContext>,
      );
      expect(e.textContent).toBe('purple');
    });
    itRenders('class child without context', async render => {
      class ClassChildWithoutContext extends React.Component {