Remove obsolete test

pre_fork is now mutually exclusive with get_socket() until post_fork
is called, so the sequence of events that the test was testing is no
longer possible.

tests/unit/dogstatsd/test_statsd.py

@@ -2028,16 +2028,3 @@ def test_max_payload_size(self):
         self.assertEqual(statsd._max_payload_size, UDP_OPTIMAL_PAYLOAD_LENGTH)
         statsd.socket_path = "/foo"
         self.assertEqual(statsd._max_payload_size, UDS_OPTIMAL_PAYLOAD_LENGTH)
-
-    def test_post_fork_locks(self):
-        def inner():
-            statsd = DogStatsd(socket_path=None, port=8125)
-            # Statsd should survive this sequence of events
-            statsd.pre_fork()
-            statsd.get_socket()
-            statsd.post_fork_parent()
-        t = Thread(target=inner)
-        t.daemon = True
-        t.start()
-        t.join(timeout=5)
-        self.assertFalse(t.is_alive())