Add YogaNode.create()

Summary:
Adds a factory method to `YogaNode`.

While this is purely redundant at the moment, it will allow experimentation in follow-up diffs. We will have concrete implementations deriving from `YogaNode` (which will be abstract).

Going through `YogaNode.create()` means that we can maintain ABI compatibility.

Reviewed By: amir-shalem

Differential Revision: D14122974

fbshipit-source-id: 15d92f296d91cc8bbd79a196f370d2dbb69b3f92

java/com/facebook/yoga/YogaNode.java

@@ -795,4 +795,12 @@ public class YogaNode implements Cloneable {
     newNode.mOwner = this;
     return newNode.mNativePointer;
   }
+
+  public static YogaNode create() {
+    return new YogaNode();
+  }
+
+  public static YogaNode create(YogaConfig config) {
+    return new YogaNode(config);
+  }
 }