Fix OOM for iterative tasks (MID-4959, MID-4615)

Model.searchObjectsIterative used thread-local repository cache.
Not completely wrong but when iterating through too many objects
the cache gets filled in. (And the data in it could get quite obsolete.)

model/model-impl/src/main/java/com/evolveum/midpoint/model/impl/controller/ModelController.java

@@ -1107,7 +1107,7 @@ public <T extends ObjectType> SearchResultMetadata searchObjectsIterative(Class<
 
 		SearchResultMetadata metadata;
 		try {
-			RepositoryCache.enter();
+			// Intentionally avoiding entering repo cache (MID-4959, MID-4615)
 			logQuery(query);
 
 			try {
@@ -1128,7 +1128,7 @@ public <T extends ObjectType> SearchResultMetadata searchObjectsIterative(Class<
 				}
 			}
 		} finally {
-			RepositoryCache.exit();
+			// Intentionally avoiding exiting repo cache
 		}
 
 		return metadata;