## Impacted versions:
 8.0 / 9.0 / 10.0
## Steps to reproduce:
* see https://github.com/odoo/odoo/issues/11841
* in a shell
  1. create an in memory record `order = self.env['purcahse.order'].new({....})`
  2. create an in memory record with a reference to the first one `order_line = self.env['purchase.order.line'].new({'order_id': order, ....})`
  3. order_line.order_id is an in memory recordset
  4. create a record for a model that inherits from mail.thread `self.env['product.product'].create({....})`
  5. At this stage order_line.order_id is an empty recordset

## Current behavior:
 In memory records are dropped when a call is done to self.invalidate_cache
## Expected behavior:
In memory records are preserved when a call is done to self.invalidate_cache


There are lot of places where the method `invalidate_cache` is called and the silent removal of the in memory records from all environments has unpredictable effects on fields modified by a computed method or an onchange or even related fields .... Moreover since all caches are invalidated each time you create / write / unlink  (https://github.com/odoo/odoo/blob/10.0/addons/mail/models/mail_followers.py#L111) an instance of a model that inherits from 'mail.thread', the performances of the server are severely penalized.

OPW703903

res = []
        for order in self.browse(cr, uid, ids, context={}):
            for line in order.order_line:
                res += [x.id for x in line.move_ids]
        return res
    def action_picking_create(self, cr, uid, ids, context=None):
        for order in self.browse(cr, uid, ids):
            picking_vals = {
                'picking_type_id': order.picking_type_id.id,
                'partner_id': order.partner_id.id,
                'date': order.date_order,
                'origin': order.name
            }
            picking_id = self.pool.get('stock.picking').create(cr, uid, picking_vals, context=context)
            self._create_stock_moves(cr, uid, order, order.order_line, picking_id, context=context)
        return picking_id
    def picking_done(self, cr, uid, ids, context=None):
        self.write(cr, uid, ids, {'shipped':1,'state':'approved'}, context=context)
        
        proc_obj = self.pool.get("procurement.order")
        po_lines = []
        for po in self.browse(cr, uid, ids, context=context):
            po_lines += [x.id for x in po.order_line if x.state != 'cancel']
        if po_lines:
            procs = proc_obj.search(cr, uid, [('purchase_line_id', 'in', po_lines)], context=context)
            if procs:
                proc_obj.check(cr, uid, procs, context=context)
        self.message_post(cr, uid, ids, body=_("Products received"), context=context)
        return True
    def do_merge(self, cr, uid, ids, context=None):