@Override
            public void run() {
              Region r1 = cache.getRegion(SEPARATOR + REGION_NAME);
              assertNotNull(r1);
              r1.put(k1, server_k1_updated);
            }
Given a server port (PORT1, PORT2, or PORT3) return its vm.

@since GemFire 5.7
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/tier/sockets/HAInterestTestCase.java