tests/it_q: add tc_enqueue/dequeue testcase

This patch is adding a simple testcase, which does the following:

* enqueue up to the limit (12 items),
* dequeue up to the limit (12 items).

Everything works as expected, unless you attempt to dequeue from
an empty queue: the test binary segfaults.  The problem is explained
and fixed in a subsequent patch.

Change-Id: Ie0edbf00e656fbe231952bdbccfd37d143e8b2b1
Related: CID#336557
diff --git a/tests/it_q/it_q_test.ok b/tests/it_q/it_q_test.ok
index 7f102c6..91ba0ce 100644
--- a/tests/it_q/it_q_test.ok
+++ b/tests/it_q/it_q_test.ok
@@ -9,6 +9,11 @@
 adding queue entries up to the limit
 attempting to add more than the limit
 
+== Entering test case tc_enqueue_dequeue
+allocating q1
+adding queue entries up to the limit
+removing queue entries up to the limit
+
 == Entering test case tc_eventfd
 allocating q1
 adding 30 queue entries up to the limit