envutil.rb: move labeled_module and labeled_class

* test/ruby/envutil.rb (labeled_module, labeled_class): move from
  test/ruby/test_module.rb.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45179 b2dd03c8-39d4-4d8f-98ff-823fe69b080e