CBQE-1843: tuq: add tests for left outer join

Change-Id: I64097ef13dd0d204c5960abdbb732f2426e13572
Reviewed-on: http://review.couchbase.org/32551
Reviewed-by: Iryna Mironava <irynamironava@yandex.ru>
Tested-by: Iryna Mironava <irynamironava@yandex.ru>