Impacted versions:

8, 9, 10, master

Steps to reproduce:

Run `odoo shell --log-level=debug_sql` on a database where accounting is installed with demo data.

```
>>> AML = env['account.move.line']
>>> AML.search([('tax_ids.amount', '=', 15)])
```

You get the following trace of 4 sql statements:

The first one is ok:
```sql
SELECT "account_tax".id FROM "account_tax" WHERE (("account_tax"."active" = %s)  AND  ("account_tax"."amount" = %s)) ORDER BY "account_tax"."sequence"  
```

The second one can be improved and is discussed in https://github.com/odoo/odoo/pull/16066, it's not the point of this issue.
```sql
SELECT "account_move_line_id" FROM "account_move_line_account_tax_rel" WHERE "account_tax_id" IN %s
```

Then it does the same query twice with apparently no good reason (at least none I understand).
```sql
SELECT "account_move_line".id FROM "account_move_line" WHERE ("account_move_line"."id" in (%s)) ORDER BY "account_move_line"."date" DESC,"account_move_line"."id" DESC 
SELECT "account_move_line".id FROM "account_move_line" WHERE ("account_move_line"."id" in (%s)) ORDER BY "account_move_line"."date" DESC,"account_move_line"."id" DESC 
```

The problem has its source [here](https://github.com/odoo/odoo/blob/b8ce0db8e105ed3c9ab4aefe8bce5028764694f4/odoo/osv/expression.py#L879): at first glance I'd say lines 879 and 880 could be replaced with

```leaf.leaf = (path[0], 'in', right_ids)```
openerp/osv/expression.py
if not ids:
                        return []
                    ids2 = model.search(cr, uid, [(parent_field, 'in', ids)], context=context)
                    return ids + recursive_children(ids2, model, parent_field)
                return [(left, 'in', recursive_children(ids, left_model, parent or left_model._parent_name))]
        def pop():
            """ Pop a leaf to process. """
            return self.stack.pop()
        def push(leaf):
            """ Push a leaf to be processed right after. """
            self.stack.append(leaf)
        def push_(leaf):
            """ Push a leaf to the s. This leaf has been fully processed
                and validated. """
            self..append(leaf)
        self. = []
        self.stack = [ExtendedLeaf(leaf, self.root_model) for leaf in self.expression]
        # 
        self.stack.reverse()
        while self.stack:
            # 
            leaf = pop()
            # 
            if leaf.is_operator():
                left, operator, right = leaf.leaf, None, None
            elif leaf.is_true_leaf() or leaf.is_false_leaf():
                # 
                left, operator, right = ('%s' % leaf.leaf[0], leaf.leaf[1], leaf.leaf[2])