[IMP] mrp: compute quantities speedup

The computation of kit quantities was not efficient. A loop on each product
of the recordset to consider performed. Each time a product was seen as 'not a kit',
a new computation on the complete recordset was done. This leads to a N^2 complexity

This commit only compute stock quantities for non kit product in one batch

opw-2070768

closes odoo/odoo#37205

Signed-off-by: Simon Lejeune (sle) <sle@openerp.com>

addons/mrp/models/product.py

@@ -91,9 +91,11 @@ class ProductProduct(models.Model):
          - 'incoming_qty'
          - 'outgoing_qty'
          """
+        kits = self.env['product.product']
         for product in self:
             bom_kit = self.env['mrp.bom']._bom_find(product=product, bom_type='phantom')
             if bom_kit:
+                kits |= product
                 boms, bom_sub_lines = bom_kit.explode(product, 1)
                 ratios_virtual_available = []
                 ratios_qty_available = []
@@ -112,8 +114,7 @@ class ProductProduct(models.Model):
                     product.qty_available = min(ratios_qty_available) // 1
                     product.incoming_qty = min(ratios_incoming_qty) // 1
                     product.outgoing_qty = min(ratios_incoming_qty) // 1
-            else:
-                super(ProductProduct, self)._compute_quantities()
+        super(ProductProduct, self - kits)._compute_quantities()
 
     @api.multi
     def action_view_bom(self):