test_super.rb: test_module_super_in_method_module

* test/ruby/test_super.rb (test_module_super_in_method_module): more
  test for the case searching super method from a method defined in a
  module.  [ruby-core:59589] [Bug #9315]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44510 b2dd03c8-39d4-4d8f-98ff-823fe69b080e