Update the repro case & sample data to clarify v5.3.16 issue

As requested in
  nhibernate/nhibernate-core#3609 (comment)
this expands the test case so that it fails in v5.3.16 as well as
5.3.17+.  It also adds some comments to the test pointing out
why it fails on 5.3.16, and why that's for a different reason to
the reason it fails in 5.3.17+.

NHibernate.PropertyRefBug.Tests/PropertyRefQueryTests.cs

@@ -23,6 +23,15 @@ public void QueryForDataWhichWasInsertedViaAdoUsingASubqueryShouldProvideExpecte
         var validOrders = session.Query<Order>().Where(x => x.CreatedDate > new DateTime(2024, 9, 10));
         var orderCount = session.Query<LineItem>().Count(x => validOrders.Any(y => y == x.Order));
 
+        // In v5.3.15 this test passes
+        // 
+        // In v5.3.16 this test fails because it returns a result of 2 and not 1.  That's occurred because the SQL WHERE generated for the EXISTS subquery is incorrect.
+        // It has entirely missed the criterion which relates LineItem to Order, so it's returning all line items without restriction.
+        // This failure reason for v5.3.16 seems to have been immediately fixed in v5.3.17, although it's still exhibiting the wrong behaviour in v5.3.17 (below).
+        //
+        // In v.5.3.17+ this test fails because it returns a result of 0 and not 1.  That's occurred because the SQL WHERE generated for the EXISTS subquery is incorrect,
+        // in a different manner to the above.  That's because it is trying to traverse the FK relationship using LineItem.OrderId and Order.Id, rather than
+        // LineItem.OrderId and Order.UniqueId.
         Assert.That(orderCount, Is.EqualTo(1));
     }
 

NHibernate.PropertyRefBug/AdoDbInitialiser.cs

@@ -22,9 +22,11 @@ Amount REAL NOT NULL
 
     const string DataSql = @"
 INSERT INTO TheOrder (Id, UniqueId, CreatedDate)
-VALUES (1, '0ab92479-8a17-4dbc-9bef-ce4344940cec', '2024-09-19T12:10:00Z');
+VALUES (1, '0ab92479-8a17-4dbc-9bef-ce4344940cec', '2024-09-19T12:10:00Z'),
+       (2, '4ca17d84-97aa-489f-8701-302a3879a388', '2021-09-19T12:20:00Z');
 INSERT INTO LineItem(Id, OrderId, ItemName, Amount)
-VALUES(1, '0ab92479-8a17-4dbc-9bef-ce4344940cec', 'Bananas', 5);";
+VALUES(1, '0ab92479-8a17-4dbc-9bef-ce4344940cec', 'Bananas', 5),
+      (2, '4ca17d84-97aa-489f-8701-302a3879a388', 'Apples', 10);";
 
     public static void CreateSchema(IDbConnection connection)
     {