Optimizer trace support for order by limit optimzation with sort-nest

For the order by limit optimization in MDEV-8306, we should add items regarding that optimization to the sort-nest

The list is:

1. Cost of sorting to be added to the trace when we consider the ORDER BY LIMIT optimzation
2. Whenever limit is applied to the record count of the partial join order, print the new partial record count to the trace
3. All the plans that considered using a sort-nest [DONE]
4. Tables inside the sort-nest [DONE]