Fabric: Checking for HasNewLayout before applying layout metrics to ShadowNode

Summary:
If the `HasNewLayout` flag is `false`, we should not copy the data from YGStyle/YGLayout to ShadowNode because the node can be already sealed and because it's unnecessary. Previously we workaround this case with a special check in `setLayoutMetrics` method, but that can be unreliable because of some side-effects related to pixel rounding and comparing floats.
The new approach is much more robust and explicit.

Reviewed By: JoshuaGross

Differential Revision: D14496939

fbshipit-source-id: deddb14d2206c5bd3f22154d0ea682e3c5888901

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

@@ -170,6 +170,10 @@ void YogaLayoutableShadowNode::layout(LayoutContext layoutContext) {
 
 void YogaLayoutableShadowNode::layoutChildren(LayoutContext layoutContext) {
   for (const auto &childYogaNode : yogaNode_.getChildren()) {
+    if (!childYogaNode->getHasNewLayout()) {
+      continue;
+    }
+
     auto childNode =
         static_cast<YogaLayoutableShadowNode *>(childYogaNode->getContext());
 

ReactCommon/fabric/core/layout/LayoutableShadowNode.cpp

@@ -22,12 +22,12 @@ LayoutMetrics LayoutableShadowNode::getLayoutMetrics() const {
 }
 
 bool LayoutableShadowNode::setLayoutMetrics(LayoutMetrics layoutMetrics) {
+  ensureUnsealed();
+
   if (layoutMetrics_ == layoutMetrics) {
     return false;
   }
 
-  ensureUnsealed();
-
   layoutMetrics_ = layoutMetrics;
   return true;
 }