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?
}).not.toThrow();
    });
    it('should warn about contentEditable and children', () => {
      expect(() =>
        mountComponent({contentEditable: true, children: ''}),
      ).toErrorDev(
        'Warning: A component is `contentEditable` and contains `children` ' +
          'managed by React. It is now your responsibility to guarantee that ' +
          'none of those nodes are unexpectedly modified or duplicated. This ' +
          'is probably not intentional.\n    in div (at **)',
      );
    });
    it('should respect suppressContentEditableWarning', () => {
      mountComponent({
        contentEditable: true,
        children: '',
        suppressContentEditableWarning: true,
      });
    });
    it('should validate against invalid styles', () => {
      expect(function() {
        mountComponent({style: 'display: none'});
      }).toThrowError(
        'The `style` prop expects a mapping from style properties to values, ' +
          "not a string. For example, style={{marginRight: spacing + 'em'}} " +
          'when using JSX.',
      );
    });
    it('should throw for children on void elements', () => {
      class X extends React.Component {