CNDB-16279: Fix DatabaseDescriptorRefTest by adding Clock and NoSpamLogger to whitelist (#2173)

### What is the issue

These missing classes are breaking DatabaseDescriptorRefTest

### What does this PR fix and why was it fixed

add them to whitelist

Author: driftx

test/unit/org/apache/cassandra/config/DatabaseDescriptorRefTest.java

@@ -207,7 +207,11 @@ public class DatabaseDescriptorRefTest
     "org.apache.cassandra.transport.ProtocolException",
     "org.apache.cassandra.utils.Closeable",
     "org.apache.cassandra.utils.CloseableIterator",
+    "org.apache.cassandra.utils.Clock",
+    "org.apache.cassandra.utils.Clock$Global",
     "org.apache.cassandra.utils.FBUtilities",
+    "org.apache.cassandra.utils.NoSpamLogger",
+    "org.apache.cassandra.utils.NoSpamLogger$Clock",
     "org.apache.cassandra.utils.Pair",
     "org.apache.cassandra.utils.StorageCompatibilityMode",
     "org.apache.cassandra.utils.binlog.BinLogOptions",