test_jit.rb: show debug info for success_count test
to investigate https://rubyci.org/logs/rubyci.s3.amazonaws.com/unstable11s/ruby-trunk/log/20181221T092505Z.fail.html.gz
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66479 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
test_jit.rb: show debug info for success_count test
to investigate
https://rubyci.org/logs/rubyci.s3.amazonaws.com/unstable11s/ruby-trunk/log/20181221T092505Z.fail.html.gz
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66479 b2dd03c8-39d4-4d8f-98ff-823fe69b080e