runner.rb: instance variable

* test/runner.rb (before_setup, after_teardown): use an instance
  variable instead of a class variable.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46452 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2014-06-17

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46453 b2dd03c8-39d4-4d8f-98ff-823fe69b080e