tests: Pass required args to select_related call for Message objects.

This commit adds code to pass all the required arguments to
select_related call for Message objects such that only the
required related fields are fetched from the database.

Previously, we did not pass any arguments to select_related,
so all the directly and indirectly related fields were fetched
when many of them were actually not being used and made the
query unnecessarily complex.

zerver/tests/test_message_edit.py

@@ -282,7 +282,8 @@ class EditMessageTest(EditMessageTestCase):
             self.send_stream_message(self.notification_bot(realm), stream_name, "Message three")
         )
         messages = [
-            Message.objects.select_related().get(id=message_id) for message_id in message_ids
+            Message.objects.select_related(*Message.DEFAULT_SELECT_RELATED).get(id=message_id)
+            for message_id in message_ids
         ]
 
         # Check number of queries performed

zerver/tests/test_message_flags.py

@@ -1454,7 +1454,8 @@ class MessageAccessTests(ZulipTestCase):
 
         message_ids = [message_one_id, message_two_id]
         messages = [
-            Message.objects.select_related().get(id=message_id) for message_id in message_ids
+            Message.objects.select_related("recipient").get(id=message_id)
+            for message_id in message_ids
         ]
 
         with self.assert_database_query_count(2):
@@ -1512,7 +1513,8 @@ class MessageAccessTests(ZulipTestCase):
 
         message_ids = [message_one_id, message_two_id]
         messages = [
-            Message.objects.select_related().get(id=message_id) for message_id in message_ids
+            Message.objects.select_related("recipient").get(id=message_id)
+            for message_id in message_ids
         ]
 
         # All public stream messages are always accessible