test_curses.rb: add sentinel
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40182 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
test_curses.rb: add sentinel
of read pty output after the child process terminated, which causes
EIO on Linux.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40182 b2dd03c8-39d4-4d8f-98ff-823fe69b080e