test_io_console.rb: investigate hang-up

* test/io/console/test_io_console.rb (TestIO_Console#test_noctty):
  grab error outputs and stop the loop upto 3 seconds.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40512 b2dd03c8-39d4-4d8f-98ff-823fe69b080e