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".
expect(field[valueKey]).toBe(initialValue);
          
          field[valueKey] = changedValue;
          resetModules();
          
          const clientField = await renderIntoDom(
            element,
            field.parentNode,
            true,
          );
          
          
          
          expect(clientField === field).toBe(true);
          
          expect(clientField[valueKey]).toBe(changedValue);
        };
        it('should not blow away user-entered text on successful reconnect to an uncontrolled input', () =>
          testUserInteractionBeforeClientRender(
            <input defaultValue="Hello" />,
          ));
        it('should not blow away user-entered text on successful reconnect to a controlled input', async () => {
          let changeCount = 0;
          await testUserInteractionBeforeClientRender(
            <ControlledInput onChange={() => changeCount++} />,
          );
          
          
          
          expect(changeCount).toBe(0);