Fix yoga node owner getting out of sync with children

Summary:
Changelog: [internal]

# Problem
We have node A with N children.

Calling cloning constructor on `YogaLayoutableShadowNode` causes new `yogaNode_` to be created.
However if `fragment.children` is nil in cloning constructor, which basically says children were not changed, then the existing children's `owner` becomes invalid.

# Solution
In the clone constructor, always call `updateYogaChildren`. This updates yoga children with the new `owner`.

Reviewed By: JoshuaGross

Differential Revision: D20139582

fbshipit-source-id: 3932694d4381b601df07dd8a57887ce7c09f1582

ReactCommon/fabric/components/view/yoga/YogaLayoutableShadowNode.cpp

@@ -61,9 +61,10 @@ YogaLayoutableShadowNode::YogaLayoutableShadowNode(
     updateYogaProps();
   }
 
-  if (fragment.children) {
-    updateYogaChildren();
-  }
+  // Yoga children have `yogaNode_` set as owner. At this point that yogaNode_
+  // is from previous `YogaLayoutableShadowNode` that is being cloned here.
+  // Calling `updateYogaChildren` is needed in order to update owner of children.
+  updateYogaChildren();
 }
 
 void YogaLayoutableShadowNode::cleanLayout() {