[ticket/12880] core.mcp_queue_!is_topics_query_before

Adding core.mcp_queue_is_topics_query_before

PHPBB3-12880
Merge pull request #2764 from brunoais/ticket/12880

[ticket/12880] core.mcp_queue_!is_topics_query_before

* brunoais/ticket/12880:
  [ticket/12880] core.mcp_queue_!is_topics_query_before