Optimize traverse_dynamic for nil and binary entries

Short-circuit the traversal of nil (unchanged) and binary entries
to avoid function call overhead and map lookups.

Author: preciz

lib/phoenix_live_view/diff.ex

@@ -615,6 +615,29 @@ defmodule Phoenix.LiveView.Diff do
     traverse_dynamic(dynamic, 0, %{}, children, pending, components, template, changed?)
   end
 
+  defp traverse_dynamic(
+         [entry | entries],
+         counter,
+         diff,
+         children,
+         pending,
+         components,
+         template,
+         changed?
+       )
+       when is_nil(entry) or (is_binary(entry) and not is_map_key(children, counter)) do
+    traverse_dynamic(
+      entries,
+      counter + 1,
+      if(is_binary(entry), do: Map.put(diff, counter, entry), else: diff),
+      children,
+      pending,
+      components,
+      template,
+      changed?
+    )
+  end
+
   defp traverse_dynamic(
          [entry | entries],
          counter,