test__socket_timeout.py: do not do kill(block=True) since blocking is default

greentest/test__socket_timeout.py

@@ -14,7 +14,7 @@ class Test(unittest.TestCase):
 
     def tearDown(self):
         self.server.close()
-        self.acceptor.kill(block=True)
+        self.acceptor.kill()
         del self.acceptor
         del self.server