old_contents: export function isStateless(component) {
    return !component.prototype.render;
  }
  
new_contents: export function isStateless(component) {
    // `function() {}` has prototype, but `() => {}` doesn't
    // `() => {}` via Babel has prototype too.
    return !(component.prototype && component.prototype.render);
  }
  
subject: Fix isStateless check for native arrow func