git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_2@55599 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
because the implementation of Object#hash is a little difference from
trunk. cf. [Backport #12391]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_2@55599 b2dd03c8-39d4-4d8f-98ff-823fe69b080e