spec/ruby/library/socket/*: fix hanging on FreeBSD 11.1

There are still other test failures which need fixing on FreeBSD.
Keep an eye on:

  http://rubyci.s3.amazonaws.com/freebsd11zfs/ruby-trunk/recent.html

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64223 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

spec/ruby/library/socket/basicsocket/send_spec.rb

@@ -200,6 +200,10 @@ describe 'BasicSocket#send' do
 
             @client.send('a', Socket::MSG_OOB).should == 1
 
+            platform_is :freebsd do # recv hangs otherwise
+              @client.close
+            end
+
             socket, _ = @server.accept
             begin
               socket.recv(1, Socket::MSG_OOB).should == 'a'