Use delete instead of free

Summary: Since a `YGNodeRef` is created with `new`, it needs to be deleted using `delete` instead of `free`.

Reviewed By: richardjrossiii

Differential Revision: D6866064

fbshipit-source-id: a44828cedb5045b6c97179fb30ffd8c8dafcbfbe

yoga/Yoga.cpp

@@ -256,7 +256,7 @@ void YGNodeFree(const YGNodeRef node) {
   }
 
   node->clearChildren();
-  free(node);
+  delete node;
   gNodeInstanceCount--;
 }