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?
itRenders(
        'no positive numeric property with zero value',
        async render => {
          const e = await render(<input size={0} />);
          expect(e.hasAttribute('size')).toBe(false);
        },
      );
      itRenders('no numeric prop with function value', async render => {
        const e = await render(<ol start={function() {}} />, 1);
        expect(e.hasAttribute('start')).toBe(false);
      });
      itRenders('no numeric prop with symbol value', async render => {
        const e = await render(<ol start={Symbol('foo')} />, 1);
        expect(e.hasAttribute('start')).toBe(false);
      });
      itRenders(
        'no positive numeric prop with function value',
        async render => {
          const e = await render(<input size={function() {}} />, 1);
          expect(e.hasAttribute('size')).toBe(false);
        },
      );
      itRenders('no positive numeric prop with symbol value', async render => {
        const e = await render(<input size={Symbol('foo')} />, 1);
        expect(e.hasAttribute('size')).toBe(false);
      });
    });
    describe('props with special meaning in React', function() {
      itRenders('no ref attribute', async render => {
        class RefComponent extends React.Component {