Same as https://github.com/facebook/react/issues/10103, but for the server renderer. You can look at implementation in https://github.com/facebook/react/pull/11168 and do something very similar in `ReactPartialRenderer.js`.
render() {
        if (this.props.flipped) {
          return (
            <div>
              <Static ref="static0" key="B">
                B (ignored)
              </Static>
              <Static ref="static1" key="A">
                A (ignored)
              </Static>
            </div>
          );
        } else {
          return (
            <div>
              <Static ref="static0" key="A">
                A
              </Static>
              <Static ref="static1" key="B">
                B
              </Static>
            </div>
          );
        }
      }
    }
    const container = document.createElement('div');
    const comp = ReactDOM.render(<Component flipped={false} />, container);
    expect(ReactDOM.findDOMNode(comp.refs.static0).textContent).toBe('A');
    expect(ReactDOM.findDOMNode(comp.refs.static1).textContent).toBe('B');