Gardening: Use subclass name in ClusterTopology.toString()

Include "ClusterTopology" or "ClusterTopologyWithBucket"
depending on the instance type.

This makes it easer to tell at a glance whether the topology
came from a bucket.

Change-Id: I6000f466eb52c903d32a7128a7136c9c4e83fdd5
Reviewed-on: https://review.couchbase.org/c/couchbase-jvm-clients/+/229143
Tested-by: Build Bot <[email protected]>
Reviewed-by: Michael Reiche <[email protected]>

Author: dnault

core-io/src/main/java/com/couchbase/client/core/topology/ClusterTopology.java

@@ -128,7 +128,7 @@ public ClusterTopologyWithBucket requireBucket() {
   public String toString() {
     String bucket = this instanceof ClusterTopologyWithBucket ? this.requireBucket().bucket().toString() : "<N/A>";
 
-    return "ClusterTopology{" +
+    return getClass().getSimpleName() + "{" +
       "revision=" + revision +
       ", clusterIdent=" + clusterIdent +
       ", tls=" + tls +