*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


it('treats updated function value as an empty string', () => {
      const container = document.createElement('div');
      ReactDOM.render(<textarea value="foo" onChange={() => {}} />, container);
      expect(() =>
        ReactDOM.render(
          <textarea value={() => {}} onChange={() => {}} />,
          container,
        ),
      ).toWarnDev('Invalid value for prop `value`');
      const node = container.firstChild;
      expect(node.value).toBe('');
    });
    it('treats initial function defaultValue as an empty string', () => {
      const container = document.createElement('div');
      ReactDOM.render(<textarea defaultValue={() => {}} />, container);
      const node = container.firstChild;
      
      expect(node.value).toBe('');
    });
    it('treats updated function defaultValue as an empty string', () => {
      const container = document.createElement('div');
      ReactDOM.render(<textarea defaultValue="foo" />, container);
      ReactDOM.render(<textarea defaultValue={() => {}} />, container);
      const node = container.firstChild;
      
      expect(node.value).toBe('foo');
    });
  });
});