OAK-11414 : making collectionutils package private

oak-commons/src/main/java/org/apache/jackrabbit/oak/commons/collections/CollectionUtils.java

@@ -21,7 +21,7 @@
 /**
  * Utility methods for collections conversions.
  */
-public class CollectionUtils {
+class CollectionUtils {
 
     // Maximum capacity for a hash based collection. (used internally by JDK).
     // Also, it helps to avoid overflow errors when calculating the capacity