Add override for AtomicReferences handling of "absent" creator properties (to become nulls)

Author: cowtowncoder

src/main/java/com/fasterxml/jackson/databind/deser/std/AtomicReferenceDeserializer.java

@@ -52,6 +52,14 @@ public Object getEmptyValue(DeserializationContext ctxt) throws JsonMappingExcep
         return getNullValue(ctxt);
     }
 
+    /**
+     * Let's actually NOT coerce missing Creator parameters into empty value.
+     */
+    @Override // @since 2.13
+    public Object getAbsentValue(DeserializationContext ctxt) throws JsonMappingException {
+        return null;
+    }
+
     @Override
     public AtomicReference<Object> referenceValue(Object contents) {
         return new AtomicReference<Object>(contents);