Do not instantiate other fields loaded eagerly

It has a cost to instantiate such fields and there is not guarantee that they
will be used. But as their values are stored in the cache, if they are needed
they can be instantiated using only the cache values.
Also there is no real benefit in instantiate two fields together.

issue10026
review341251002

trytond/model/modelstorage.py

@@ -1624,6 +1624,7 @@ class ModelStorage(Model):
                 read_data = self.read(list(index.keys()), list(ffields.keys()))
                 read_data.sort(key=lambda r: index[r['id']])
             # create browse records for 'remote' models
+            no_local_cache = {'one2one', 'one2many', 'many2many', 'binary'}
             for data in read_data:
                 id_ = data['id']
                 to_delete = set()
@@ -1632,12 +1633,16 @@ class ModelStorage(Model):
                     if field._type in {
                             'many2one', 'one2one', 'one2many', 'many2many',
                             'reference'}:
+                        if (fname != name
+                                and not require_context_field
+                                and field._type not in no_local_cache):
+                            continue
                         fvalue = instantiate(field, data[fname], data)
                     if id_ == self.id and fname == name:
                         value = fvalue
-                    self._local_cache[id_][fname] = fvalue
-                    if (field._type in {
-                                'one2one', 'one2many', 'many2many', 'binary'}
+                    if fname not in self._local_cache[id_]:
+                        self._local_cache[id_][fname] = fvalue
+                    if (field._type in no_local_cache
                             or field.context
                             or getattr(field, 'datetime_field', None)
                             or isinstance(field, fields.Function)):