We were using `Object.create` to setup the prototype chain at the start of the class definition, which lead to #7771.
I was a bit worried about a speed hit, but it seems everyone optimizes the two patterns the same way.
https://jsbench.github.io/#f9fca52407643d96458a35763b201215Fixes#7771.
* Fix class properties after nested class' bare super
Fixes#7371.
* Fix node 4 test
* This damn node 4 test
* All of the ClassBody, but not the methods or field inits
* tmp
* tmp
* Use common class environment visitor
* Tests
* Use skipKey to avoid recursive traversal
* Remove old state
* Use jest expect
* Properly traverse nested class for supers
* Add object nested in class cases
* Add object nested object cases
* Test class properties
* Undo changes to lerna.json
* Add tests arournd prefix/postfix super increment
* tmp
* Use sets
