Factor out push_node, respect offset

This saves a couple lines of code, and will save more when I use the
lambda again in some subsequent changes ... but more importantly, it
makes the coordinate offset parameter get respected by discontinuous
output, not just continuous output.

Let's get that into CI before I go any further, and see if there are any
Moose tests that are comparing to inconsistent gold results.

src/mesh/exodusII_io_helper.C

@@ -2118,6 +2118,21 @@ void ExodusII_IO_Helper::write_nodal_coordinates(const MeshBase & mesh, bool use
   y.reserve(num_nodes);
   z.reserve(num_nodes);
 
+  auto push_node = [this](const Point & p) {
+    x.push_back(p(0) + _coordinate_offset(0));
+
+#if LIBMESH_DIM > 1
+    y.push_back(p(1) + _coordinate_offset(1));
+#else
+    y.push_back(0.);
+#endif
+#if LIBMESH_DIM > 2
+    z.push_back(p(2) + _coordinate_offset(2));
+#else
+    z.push_back(0.);
+#endif
+  };
+
   // And in the node_num_map - since the nodes aren't organized in
   // blocks, libmesh will always write out the identity map
   // here... unless there has been some refinement and coarsening, or
@@ -2135,18 +2150,8 @@ void ExodusII_IO_Helper::write_nodal_coordinates(const MeshBase & mesh, bool use
         {
           const Node & node = *node_ptr;
 
-          x.push_back(node(0) + _coordinate_offset(0));
+          push_node(node);
 
-#if LIBMESH_DIM > 1
-          y.push_back(node(1) + _coordinate_offset(1));
-#else
-          y.push_back(0.);
-#endif
-#if LIBMESH_DIM > 2
-          z.push_back(node(2) + _coordinate_offset(2));
-#else
-          z.push_back(0.);
-#endif
 
           // Fill in node_num_map entry with the proper (1-based) node id
           node_num_map.push_back(node.id() + 1);
@@ -2162,17 +2167,7 @@ void ExodusII_IO_Helper::write_nodal_coordinates(const MeshBase & mesh, bool use
       for (const auto & elem : mesh.active_element_ptr_range())
         for (const Node & node : elem->node_ref_range())
           {
-            x.push_back(node(0));
-#if LIBMESH_DIM > 1
-            y.push_back(node(1));
-#else
-            y.push_back(0.);
-#endif
-#if LIBMESH_DIM > 2
-            z.push_back(node(2));
-#else
-            z.push_back(0.);
-#endif
+            push_node(node);
 
             // Let's skip the node_num_map in the discontinuous
             // case, since we're effectively duplicating nodes for