CBQE-1895: tuq: implement tests for key+array expr

Change-Id: I89cd2199d4a0e45eae495282d810269714b01d22
Reviewed-on: http://review.couchbase.org/32685
Reviewed-by: Iryna Mironava <irynamironava@yandex.ru>
Tested-by: Iryna Mironava <irynamironava@yandex.ru>