When setting boolean attributes on Web Components
`<x-search somebool name={this.props.name} />`
they get rendered as attribute/value pairs instead
`<x-search somebool="true" name={this.props.name}>`

This causes problems with some AMP components, for eg. `<amp-iframe />` which has a `resizable` attribute that gets rendered as `resizable="true"`. This results in non valid AMP content and developers crying with blood tears on their keyboards :)
> The attribute 'resizable' in tag 'amp-iframe' is set to the invalid value 'true'. (see https://www.ampproject.org/docs/reference/components/amp-iframe)

Is there any reason for the current behaviour? Will changing this break something else?
children = propValue;
          break;
        case 'dangerouslySetInnerHTML':
          
          
          innerHTML = propValue;
          break;
        case 'defaultValue':
        case 'value':
          
          break;
        default:
          pushAttribute(target, responseState, propKey, propValue);
          break;
      }
    }
  }
  target.push(endOfStartTag);
  pushInnerHTML(target, innerHTML, children);
  return children;
}
function flattenOptionChildren(children: mixed): string {
  let content = '';
  
  
  Children.forEach((children: any), function(child) {
    if (child == null) {
      return;
    }
    content += (child: any);