dillon1000/react

Throw more specific error if passed undefined in React.cloneElement (#12534)

* throw error if passed undefined

* should be TypeError

* simplify

* use invariant

* editor messed up spacing

* better check

* Revert "better check"

This reverts commit 273370758eafa54d329577b3dc942c70587eccd3.

* yarn prettier test was failing

* more explicit copy

* es6 import

* tests

* formatting

* Move import