[hbase] Change test_list_tables hbase test to query each cluster name, rather than hardcoded values

The test_list_tables hbase test sends a post request to a uri suffixed by a cluster name. In the old test, it was hardcoded to "Cluster". However, hbase clusters may not be named that, and there might be more than one. This change just adds a simple for-each loop, giving the test the ability to verify functionality for each hbase cluster, and the ability to accept situations where the hbase cluster is not named "Cluster"