Summary:
@public
Encapsulates node cloning within `YGConfig`.
This is necessary for allowing for context-aware cloning functions, which will ultimately allow for removal of weak global JNI references.
Reviewed By: shergin
Differential Revision: D14132608
fbshipit-source-id: 0dec114c8e172b1e34a4b7fd146c43f13c151ade