@After
  public void tearDown() throws Exception {
    for (VM vm : toArray(managerVM, memberVM1, memberVM2, memberVM3)) {
      vm.invoke(() -> {
        if (cache != null) {
          cache.close();
        }
        cache = null;
        alertingService = null;
        notificationListener = null;
        distributedSystemMXBean = null;
      });
    }
  }
Distributed tests for {@link DistributedSystemMXBean} with alerts. Extracted from
{@link DistributedSystemMXBeanDistributedTest}.
geode-core/src/distributedTest/java/org/apache/geode/management/DistributedSystemMXBeanWithAlertsDistributedTest.java