*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


const node = ((element: any): TextAreaWithWrapperState);
  const value = getToStringValue(props.value);
  const defaultValue = getToStringValue(props.defaultValue);
  if (value != null) {
    
    
    const newValue = toString(value);
    
    if (newValue !== node.value) {
      node.value = newValue;
    }
    if (props.defaultValue == null && node.defaultValue !== newValue) {
      node.defaultValue = newValue;
    }
  }
  if (defaultValue != null) {
    node.defaultValue = toString(defaultValue);
  }
}
export function postMountWrapper(element: Element, props: Object) {