[ticket/12382] Add template test for subloops inside events

PHPBB3-12382
[ticket/12382] Add template test for subloops inside includes

PHPBB3-12382
[ticket/12382] Mark broken nested loop with include as incomplete

PHPBB3-12382
Merge remote-tracking branch 'nickvergessen/ticket/12382' into develop-ascraeus

* nickvergessen/ticket/12382:
  [ticket/12382] Mark broken nested loop with include as incomplete
  [ticket/12382] Add template test for subloops inside includes
  [ticket/12382] Add template test for subloops inside events