Summary:
This diff adds more enforcement for consistency of `ShadowNodeMutation`s, including:
* `Props` object for newly created or updated view must not be nullptr;
* `oldShadowView` must describe the previous state of the view for `Update` instruction;
* `ignoreDuplicateCreates` option was removed.
I suspect some of the crashes we see in Fabric are caused by a violation of one of these constraints. If one of these fails in debug builds, we will get an early signal.
Changelog: [Internal]
Reviewed By: JoshuaGross
Differential Revision: D24880821
fbshipit-source-id: 8c8a3d8e205ce34f6e0335e8a2b0cf676930c284
Samuel Susla
Valentin Shergin
David Vacca