RubyVM class serial is no longer available in Ruby 3.2

since ruby/ruby@13bd617

Author: amatsuda

activesupport/test/executor_test.rb

@@ -226,7 +226,7 @@ def test_hook_insertion_order
   end
 
   def test_class_serial_is_unaffected
-    skip if !defined?(RubyVM)
+    skip if !defined?(RubyVM) || !RubyVM.stat.has_key?(:class_serial)
 
     hook = Class.new do
       define_method(:run) do