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".
'a newline-eating tag with content not starting with \\n',
        async render => {
          const e = await render(<pre>Hello</pre>);
          expect(e.textContent).toBe('Hello');
        },
      );
      itRenders(
        'a newline-eating tag with content starting with \\n',
        async render => {
          const e = await render(<pre>{'\nHello'}</pre>);
          expect(e.textContent).toBe('\nHello');
        },
      );
      itRenders('a normal tag with content starting with \\n', async render => {
        const e = await render(<div>{'\nHello'}</div>);
        expect(e.textContent).toBe('\nHello');
      });
    });
    describe('different component implementations', function() {
      function checkFooDiv(e) {
        expect(e.childNodes.length).toBe(1);
        expectNode(e.firstChild, TEXT_NODE_TYPE, 'foo');
      }
      itRenders('stateless components', async render => {
        const StatelessComponent = () => <div>foo</div>;
        checkFooDiv(await render(<StatelessComponent />));
      });
      itRenders('ES6 class components', async render => {
        class ClassComponent extends React.Component {
          render() {