When creating an Element with a ref from inside of a constructor an error is thrown in production mode, but not in dev mode.

Here is a minimal sample:
https://jsfiddle.net/84v837e9/35/

An error, "Only a ReactOwner can have refs", should happen in dev and production modes.

This is happening in React 15.4
return {
        render() {
          return <div ref="elemRef" />;
        },
      };
    }
    const inst = ReactTestUtils.renderIntoDocument(<Comp />);
    expect(inst.refs.elemRef.tagName).toBe('DIV');
  });
});
/**
 * Tests that when a ref hops around children, we can track that correctly.
 */
describe('ref swapping', () => {
  let RefHopsAround;
  beforeEach(() => {
    jest.resetModules();
    React = require('react');
    ReactTestUtils = require('react-dom/test-utils');
    RefHopsAround = class extends React.Component {
      state = {count: 0};
      moveRef = () => {
        this.setState({count: this.state.count + 1});
      };
      render() {
        var count = this.state.count;
        /**