CBQE-2470: add initial n1ql 2i index tests

Change-Id: I4303bed5a7a1c48422d9a8a7079c685803e4e60c
Reviewed-on: http://review.couchbase.org/43083
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Ketaki Gangal <ketakigangal@gmail.com>