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?
});
    it('should support custom elements which extend native elements', () => {
      const container = document.createElement('div');
      spyOnDevAndProd(document, 'createElement').and.callThrough();
      ReactDOM.render(<div is="custom-div" />, container);
      expect(document.createElement).toHaveBeenCalledWith('div', {
        is: 'custom-div',
      });
    });
    it('should work load and error events on <image> element in SVG', () => {
      spyOnDevAndProd(console, 'log');
      const container = document.createElement('div');
      ReactDOM.render(
        <svg>
          <image
            xlinkHref="http://example.org/image"
            onError={e => console.log('onError called')}
            onLoad={e => console.log('onLoad called')}
          />
        </svg>,
        container,
      );
      const loadEvent = document.createEvent('Event');
      const errorEvent = document.createEvent('Event');
      loadEvent.initEvent('load', false, false);
      errorEvent.initEvent('error', false, false);
      container.getElementsByTagName('image')[0].dispatchEvent(errorEvent);
      container.getElementsByTagName('image')[0].dispatchEvent(loadEvent);
      if (__DEV__) {
        expect(console.log).toHaveBeenCalledTimes(2);