Fixed ALF-4512: MLText and NULL storage problems

- Synchronizing the cached values with the low-level DB keys had problems for some use-cases
   - Switching from null ML value in default locale (real null) to null value in a specific locale
   - Switching from d:any empty array to d:any empty array of empty arrays
   - other odd cases
 - Refactored the differencing code to do high-level differences
   - This makes it easier to take care of the switches between properties states
   - Sacrifices on performance when dealing with 100K multivalued properties


git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@22059 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/repo/node/BaseNodeServiceTest.java

@@ -1909,7 +1909,7 @@ public abstract class BaseNodeServiceTest extends BaseSpringTest
                 QName.createQName("pathA"),
                 TYPE_QNAME_TEST_MANY_PROPERTIES).getChildRef();
 
-        for (int inc = 0; inc < 3; inc++)
+        for (int inc = 0; inc < 5; inc++)
         {
             System.out.println("----------------------------------------------");
             int collectionSize = (int) Math.pow(10, inc);