Disable restoreDefaultValues in Native Animated in Fabric

Summary:
Changelog: [Internal]

# Problem

Before every update, restoreDefaults is called on animated nodes. In paper this makes sure no stale properties are on animated nodes. In paper it works fine because restoreDefaults is called before mounting and animations are triggered after mounting within single commit.

Details: https://github.com/facebook/react-native/pull/11819

In Fabric however it is called outside of other mounting operations and it applies default values to the view and then re-applies animated values.

Reviewed By: JoshuaGross

Differential Revision: D21786765

fbshipit-source-id: a2cb6d6d9cbd39d4c403c97c2f51e7d92078102f

Libraries/NativeAnimation/Nodes/RCTPropsAnimatedNode.m

@@ -75,6 +75,11 @@
 
 - (void)restoreDefaultValues
 {
+  if (_managedByFabric) {
+    // Restoring to default values causes render of inconsistent state
+    // to the user because it isn't synchonised with Fabric's UIManager.
+    return;
+  }
   // Restore the default value for all props that were modified by this node.
   for (NSString *key in _propsDictionary.allKeys) {
     _propsDictionary[key] = [NSNull null];