test_io_console.rb: chomp results

* test/io/console/test_io_console.rb (run_pty): IO#readlines
  ignores the given block.  need map to chomp the results.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48987 b2dd03c8-39d4-4d8f-98ff-823fe69b080e