Issue
=====
In the test `test_stock_landed_costs_lots`, there is this `assertRecordValues`:

```python
self.assertRecordValues(lc.stock_valuation_layer_ids.sorted('product_id'), [
    {'lot_id': lot_product_b[0].id, 'product_id': product2.id, 'stock_valuation_layer_id': og_p2_layers[0].id, 'quantity': 0, 'value': 1.5},
    {'lot_id': lot_product_b[1].id, 'product_id': product2.id, 'stock_valuation_layer_id': og_p2_layers[1].id, 'quantity': 0, 'value': 1.5},
    {'lot_id': lot_product_a[0].id, 'product_id': self.product1.id, 'stock_valuation_layer_id': og_p1_layers[0].id, 'quantity': 0, 'value': 1},
    {'lot_id': lot_product_a[1].id, 'product_id': self.product1.id, 'stock_valuation_layer_id': og_p1_layers[1].id, 'quantity': 0, 'value': 1},
    {'lot_id': lot_product_a[2].id, 'product_id': self.product1.id, 'stock_valuation_layer_id': og_p1_layers[2].id, 'quantity': 0, 'value': 1},
])
```
This issue is sometime the records order is not the expected one.

Cause of the issue
==================

By doing `recordset.sorted('product_id')`, it will sort the records by compare their `product_id` records, using the python built-in `sorted`. The built-in `sorted` function simply check if record A is lower than record B, using the < operation. But in Odoo, comparing two recordsets is equal than comparing their ids as a `set`:
```python
def __lt__(self, other):
    try:
        if self._name == other._name:
            return set(self._ids) < set(other._ids)
    except AttributeError:
        pass
    return NotImplemented
```
In python, the comparaison between two sets compares is a set is a subset of the other one, which means than:
```python
{1} < {2}     # is false
{1} < {2, 1}  # is true
```
So, comparing SVLs by their product won't sort them by their product's id. If we want to do that, we have to explicitly do it by passing a function as the `sorted` `key` argument.

For more information, see:
-https://docs.python.org/3/library/functions.html#sorted -https://docs.python.org/3/reference/expressions.html#comparisons

runbot-build-error: 99086