*Bug*

When a `textarea` has the `required` attribute it renders in the invalid state using FireFox. 

This behavior is visible here: https://codesandbox.io/s/rough-frog-f00ow. Remember to view it in FireFox.  

I expect the required field to validate on form submit and not before. 

I have tested this with FireFox 68 and 69 and React 16.8.6

This appears appears to be a re-occurrence of: https://github.com/facebook/react/issues/8395


expect(() => {
      node = renderTextarea(stub, container);
    }).toWarnDev(
      'Use the `defaultValue` or `value` props instead of setting children on <textarea>.',
    );
    expect(node.value).toBe('giraffe');
    
    stub = ReactDOM.render(<textarea>gorilla</textarea>, container);
    expect(node.value).toEqual('giraffe');
  });
  it('should keep value when switching to uncontrolled element if not changed', () => {
    const container = document.createElement('div');
    const node = renderTextarea(
      <textarea value="kitten" onChange={emptyFunction} />,
      container,
    );
    expect(node.value).toBe('kitten');
    ReactDOM.render(<textarea defaultValue="gorilla" />, container);
    expect(node.value).toEqual('kitten');
  });
  it('should keep value when switching to uncontrolled element if changed', () => {
    const container = document.createElement('div');
    const node = renderTextarea(
      <textarea value="kitten" onChange={emptyFunction} />,
      container,
    );
    expect(node.value).toBe('kitten');
    ReactDOM.render(
      <textarea value="puppies" onChange={emptyFunction} />,
      container,