@Test
  public void testImpactOfBalanceClusterOverall() throws Exception {
    testImpactOfBalanceClusterOverall(false);
  }
Test the load balancing algorithm. Invariant is that all servers should be hosting either
floor(average) or ceiling(average) at both table level and cluster level Deliberately generate
a special case to show the overall strategy can achieve cluster level balance while the bytable
strategy cannot
hbase-balancer/src/test/java/org/apache/hadoop/hbase/master/balancer/TestSimpleLoadBalancer.java