Merge pull request #2964 from nickvergessen/ticket/12963

[ticket/12963] Correctly load migration files from migration/ in tests as well

* nickvergessen/ticket/12963:
  [ticket/12963] Correctly load migration files from migration/ in tests as well
[ticket/12963] Fix the migration's finder for the tests (path, new instance)

PHPBB3-12963
[ticket/13068] Language correction in FIELD_IS_CONTACT_EXPLAIN

PHPBB3-13068
Merge remote-tracking branch 'Nicofuma/ticket/12963' into develop-ascraeus

* Nicofuma/ticket/12963:
  [ticket/12963] Fix the migration's finder for the tests (path, new instance)
Merge remote-tracking branch 'GiampaoloFalqui/develop-ascraeus' into develop-ascraeus

* GiampaoloFalqui/develop-ascraeus:
  [ticket/13068] Language correction in FIELD_IS_CONTACT_EXPLAIN
[ticket/12963] Revert back to "migrations" folder name for extensions

The issues that can be created with the name change are just too much

PHPBB3-12963