[IMP] website: perf - clear cache only when needed

Before this commit, the cache would always been cleared even if not needed.
Now, we only clear cache when needed.

Util:
Introduced with https://github.com/odoo/odoo/commit/9920f20e4c7753bc17bea71dea3a90f7de687196#diff-1407a8ce197a04eefaefa26c127a4418R327
Changed with 0d5fcdc1c7

task-2211013

addons/website/tests/test_performance.py

@@ -119,4 +119,4 @@ class TestWebsitePerformance(UtilPerf):
         # assets route /web/content/..
         self.url_open('/')  # create assets attachments
         assets_url = self.env['ir.attachment'].search([('url', '=like', '/web/content/%/web.assets_common%.js')], limit=1).url
-        self.assertEqual(self._get_url_hot_query(assets_url), 6)
+        self.assertEqual(self._get_url_hot_query(assets_url), 5)

odoo/addons/base/models/ir_http.py

@@ -318,7 +318,8 @@ class IrHttp(models.AbstractModel):
             # We have prefetched some fields of record, among which the field
             # 'write_date' used by '__last_update' below. In order to check
             # access on record, we have to invalidate its cache first.
-            record._cache.clear()
+            if not record.env.su:
+                record._cache.clear()
             record['__last_update']
         except AccessError:
             return None, 403