update isSorted after shuffling

A list can be sorted after shuffling. The trivial cases are
the empty list and a list with only one element or lists 
with only identical elements. Lists with only a few elements 
have a non-negligible chance to be sorted after shuffling.

primitiveCollections/src/main/java/org/lucares/collections/IntList.java

@@ -556,7 +556,12 @@ public final class IntList implements Serializable, Cloneable {
 			data[other] = data[i];
 			data[i] = tmp;
 		}
-		sorted = false;
+
+		// update sorted
+		sorted = true;
+		for (int i = 1; i < size && sorted; i++) {
+			sorted = data[i - 1] <= data[i];
+		}
 	}
 
 	private void ensureCapacity(final int newElements) {