dillon1000/react

Inline some internals, reduce shared/ utilities between isomorphic and renderers (#9903)

* Make ReactControlledValuePropTypes DEV-only

* Remove canDefineProperty

This breaks IE8. We don't support it.

* Remove getNextDebugID

It was added temporarily to avoid Stack shared state issues across renderers.
Not a problem anymore.

* Make KeyEscapeUtils.unescape() DEV-only

* Remove unused deprecated() module

It's unlikely we'll deprecate anything else on React.* object soon.

* Inline getIteratorFn at the call sites

* Inline ReactElementSymbol

* Inline KeyEscapeUtils into Children and move the file into Stack

It's only used in one place in isomorphic.
It's used more broadly in Stack so we move it there to die.

* Update artifacts

* Reorder declarations for consistency

* Fix Flow