[ticket/11493] add check for phpBB Debug in functional tests

PHPBB3-11493
[ticket/11493] add checks for Notice and Warning

PHPBB3-11493
Merge remote-tracking branch 'dhruvgoel92/ticket/11493' into develop-olympus

* dhruvgoel92/ticket/11493:
  [ticket/11493] add checks for Notice and Warning
  [ticket/11493] add check for phpBB Debug in functional tests