Make utils.universalUnmount work with all components

There was a common pattern to universally unmount any React component.
Now it doesn't work with component which render to null, so I created
this workaround and a bug in React's Github:

https://github.com/facebook/react/issues/2545

Closes-Bug: #1393367

Change-Id: Id7f7b8f4daa7f4d8272a1fe8362cbad31f680a12
Merge "Make utils.universalUnmount work with all components"