@Test
  public void testInstantiators() throws Exception {
    PORT1 = initServerCache(server1);
    PORT2 = initServerCache(server2);

    client1.invoke(() -> InstantiatorPropagationDUnitTest
        .createClientCache(NetworkUtils.getServerHostName(server1.getHost()), PORT1));
    client2.invoke(() -> InstantiatorPropagationDUnitTest
        .createClientCache(NetworkUtils.getServerHostName(server1.getHost()), PORT2));

    unregisterInstantiatorsInAllVMs();

    // wait for client2 to come online
    Wait.pause(2000);

    client1.invoke(InstantiatorPropagationDUnitTest::registerTestObject10);
    Wait.pause(4000);

    server1.invoke(InstantiatorPropagationDUnitTest::registerTestObject11);
    Wait.pause(4000);

    server2.invoke(() -> InstantiatorPropagationDUnitTest.verifyInstantiators(2));

    server1.invoke(() -> InstantiatorPropagationDUnitTest.verifyInstantiators(2));

    client1.invoke(() -> InstantiatorPropagationDUnitTest.verifyInstantiators(2));

    client2.invoke(() -> InstantiatorPropagationDUnitTest.verifyInstantiators(2));

    unregisterInstantiatorsInAllVMs();
  }
2 clients n 2 servers.Registered instantiators on both client n server to check if propagation
of instantiators to n fro (from client n server) is taking place.Diff from the previous test in
the case that server is not stopped.So registering an instantiator on server should propagate
that to client as well.
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/tier/sockets/InstantiatorPropagationDUnitTest.java