Use last known memberlist in reconnect

[sancar]

Current behaviour: It clears the last known memberlist in reconnect here:
https://github.com/hazelcast/hazelcast-python-client/blob/master/hazelcast/cluster.py#L220

We expect a test like following to pass normally:

    def test_reconnect_toNewNode_ViaLastMemberList(self):
        old_member = self.cluster.start_member()
        config = ClientConfig()
        config.network_config.addresses.append("127.0.0.1:5701")
        config.network_config.smart_routing = False
        config.network_config.connection_attempt_limit = 100
        client = self.create_client(config)
        new_member = self.cluster.start_member()
        old_member.shutdown()

        def assert_member_list():
            self.assertEqual(1, len(client.cluster.members))
            self.assertEqual(new_member.uuid, client.cluster.members[0].uuid)

        self.assertTrueEventually(assert_member_list)