Fix BigInteger/BigDecimal cloning

These objects are immutable so there's no point in cloning them.

infra/prism-api/src/main/java/com/evolveum/midpoint/prism/util/CloneUtil.java

@@ -19,6 +19,8 @@
 import java.lang.reflect.Array;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
+import java.math.BigDecimal;
+import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
@@ -124,6 +126,10 @@ public static <T> T clone(T orig) {
 			//noinspection unchecked
 			return (T) XmlTypeConverter.createDuration(((Duration) orig));
 		}
+		if (orig instanceof BigInteger || orig instanceof BigDecimal) {
+			// todo could we use "instanceof Number" here instead?
+			return (T) orig;
+		}
 		if (orig instanceof Cloneable) {
 			T clone = javaLangClone(orig);
 			if (clone != null) {