[FIX+IMP] account_chart_update: Create taxes in batch

With this, we gain some performance, but also prevent an error if there are template
taxes that have children taxes, as Odoo standard method forces that in the same call
all of them are created simultaneously, or it will enter in an infinite loop.

account_chart_update/wizard/wizard_chart_update.py

@@ -773,18 +773,18 @@ class WizardUpdateChartsAccounts(models.TransientModel):
     @api.multi
     def _update_taxes(self):
         """Process taxes to create/update/deactivate."""
-        for wiz_tax in self.tax_ids:
+        # First create taxes in batch
+        taxes_to_create = self.tax_ids.filtered(lambda x: x.type == 'new')
+        taxes_to_create.mapped('tax_id')._generate_tax(self.company_id)
+        for wiz_tax in taxes_to_create:
+            _logger.info(_("Created tax %s."), "'%s'" % wiz_tax.tax_id.name)
+        for wiz_tax in self.tax_ids.filtered(lambda x: x.type != 'new'):
             template, tax = wiz_tax.tax_id, wiz_tax.update_tax_id
             # Deactivate tax
             if wiz_tax.type == 'deleted':
                 tax.active = False
                 _logger.info(_("Deactivated tax %s."), "'%s'" % tax.name)
                 continue
-            # Create tax
-            if wiz_tax.type == 'new':
-                template._generate_tax(self.company_id)
-                _logger.info(_("Created tax %s."), "'%s'" % template.name)
-            # Update tax
             else:
                 for key, value in self.diff_fields(template, tax).items():
                     # We defer update because account might not be created yet