[ticket/13203] Add method for byte by byte comparison to drivers helper

PHPBB3-13203
[ticket/13203] Use string_compare method in passwords drivers

PHPBB3-13203
[ticket/13203] Fix passwords manager tests

PHPBB3-13203
Merge pull request #3056 from marc1706/ticket/13203

[ticket/13203] Use constant time comparison method for comparing password hashes
Merge branch 'develop-ascraeus' into develop

* develop-ascraeus:
  [ticket/13203] Fix passwords manager tests
  [ticket/13203] Use string_compare method in passwords drivers
  [ticket/13203] Add method for byte by byte comparison to drivers helper