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?
const e = await render(<a download={true} />);
        expect(e.getAttribute('download')).toBe('');
      });
      itRenders('download prop with false value', async render => {
        const e = await render(<a download={false} />);
        expect(e.getAttribute('download')).toBe(null);
      });
      itRenders('download prop with string value', async render => {
        const e = await render(<a download="myfile" />);
        expect(e.getAttribute('download')).toBe('myfile');
      });
      itRenders('download prop with string "false" value', async render => {
        const e = await render(<a download="false" />);
        expect(e.getAttribute('download')).toBe('false');
      });
      itRenders('download prop with string "true" value', async render => {
        const e = await render(<a download={'true'} />);
        expect(e.getAttribute('download')).toBe('true');
      });
      itRenders('download prop with number 0 value', async render => {
        const e = await render(<a download={0} />);
        expect(e.getAttribute('download')).toBe('0');
      });
      itRenders('no download prop with null value', async render => {
        const e = await render(<div download={null} />);
        expect(e.hasAttribute('download')).toBe(false);
      });
      itRenders('no download prop with undefined value', async render => {
        const e = await render(<div download={undefined} />);
        expect(e.hasAttribute('download')).toBe(false);