CBD-914: added kv litmus tests

Change-Id: Ia757eb097edc8fcc054d612e7d2f44cee19d8a48
Reviewed-on: http://review.couchbase.org/25318
Reviewed-by: Ronnie Sun <ronnie@couchbase.com>
Tested-by: Ronnie Sun <ronnie@couchbase.com>