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?
<div className="foo5" />
            <div className="foo6" />
          </div>,
        ),
      ).toErrorDev([
        'Invalid DOM property `class`. Did you mean `className`?\n    in span (at **)',
        'Invalid event handler property `onclick`. Did you mean `onClick`?\n    in strong (at **)',
      ]);
    });
    it('gives source code refs for unknown prop warning for exact elements (ssr)', () => {
      expect(() =>
        ReactDOMServer.renderToString(
          <div className="foo1">
            <span class="foo2" />
            <div onClick="foo3" />
            <strong onclick="foo4" />
            <div className="foo5" />
            <div className="foo6" />
          </div>,
        ),
      ).toErrorDev([
        'Invalid DOM property `class`. Did you mean `className`?\n    in span (at **)',
        'Invalid event handler property `onclick`. ' +
          'React events use the camelCase naming convention, for example `onClick`.' +
          '\n    in strong (at **)',
      ]);
    });
    it('gives source code refs for unknown prop warning for exact elements in composition', () => {
      const container = document.createElement('div');
      class Parent extends React.Component {