Test against Class#new and not Class.new for the "is it #new from Cla…

…ss" check

* On CRuby this makes currently no difference (there is no Class.new, only Class#new),
  but on TruffleRuby there is both (in order for Class objects to be fully initialized on creation).

lib/rspec/mocks/method_reference.rb

@@ -193,7 +193,7 @@ def self.applies_to?(method_name)
       end
 
       if RUBY_VERSION.to_i >= 3
-        CLASS_NEW = ::Class.singleton_class.instance_method(:new)
+        CLASS_NEW = ::Class.instance_method(:new)
 
         def self.uses_class_new?(klass)
           ::RSpec::Support.method_handle_for(klass, :new) == CLASS_NEW.bind(klass)