[ticket/12724] Add Squiz.PHP.Eval in the legacy ruleset

PHPBB3-12724
Merge pull request #2605 from Nicofuma/ticket/12724

[ticket/12724] Add Squiz.PHP.Eval in the legacy ruleset

* Nicofuma/ticket/12724:
  [ticket/12724] Add Squiz.PHP.Eval in the legacy ruleset