skip on Solaris 11

On Solaris 11, MSG_OOB is in readfds?
http://rubyci.org/logs/rubyci.s3.amazonaws.com/unstable11x/ruby-trunk/log/20170523T152403Z.fail.html.gz
http://rubyci.org/logs/rubyci.s3.amazonaws.com/unstable11s/ruby-trunk/log/20170523T152503Z.fail.html.gz

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58861 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_io.rb

@@ -3555,6 +3555,10 @@ __END__
   end
 
   def test_select_exceptfds
+    if Etc.uname[:sysname] == 'SunOS' && Etc.uname[:release] == '5.11'
+      skip "Solaris 11 fails this"
+    end
+
     TCPServer.open('localhost', 0) do |svr|
       con = TCPSocket.new('localhost', svr.addr[1])
       acc = svr.accept