Fix three ResourceWarnings.
Mimic the clientTearDown from ThreadedTCPSocketTest, closing the socket.
diff --git a/Lib/test/test_socket.py b/Lib/test/test_socket.py
index 704d46e..facb065 100644
--- a/Lib/test/test_socket.py
+++ b/Lib/test/test_socket.py
@@ -197,6 +197,11 @@
     def clientSetUp(self):
         self.cli = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
 
+    def clientTearDown(self):
+        self.cli.close()
+        self.cli = None
+        ThreadableTest.clientTearDown(self)
+
 class SocketConnectedTest(ThreadedTCPSocketTest):
     """Socket tests for client-server connection.