[ruby-cvs:78695] a83c46e3fd (master): Add more debug info

Kazuhiro NISHIYAMA	2019-12-15 20:03:47 +0900 (Sun, 15 Dec 2019)

  New Revision: a83c46e3fd

  https://github.com/ruby/ruby/commit/a83c46e3fd

  Log:
    Add more debug info
    
    closed server doesn't have useful info.
    So call inspect before close.
    And add local debug code in comment.
    
    https://rubyci.org/logs/rubyci.s3.amazonaws.com/unstable11x/ruby-master/log/20191215T092405Z.fail.html.gz
    ```
      1) Failure:
    IMAPTest#test_connection_closed_without_greeting [/export/home/rubyci/chkbuild-tmp/tmp/build/20191215T092405Z/ruby/test/net/imap/test_imap.rb:483]:
    [Net::IMAP::Error] exception expected, not #<RuntimeError: {:e=>#<Errno::EINVAL: Invalid argument - connect(2) for [::1]:41748>, :server=>#<TCPServer:(closed)>, :port=>41748, :server_addr=>"::1"}>.
    ```

  Modified files:
    test/net/imap/test_imap.rb