test_bmethod.rb: super in bmethod test

* test/-ext-/proc/test_bmethod.rb (test_super_in_bmethod): super
  in bmethod test for [Feature #10195].

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48349 b2dd03c8-39d4-4d8f-98ff-823fe69b080e