unittests: clean up memory for counter tests

src/counters.c

@@ -1399,15 +1399,13 @@ static int StatsTestCounterReg04(void)
 static int StatsTestGetCntArray05(void)
 {
     ThreadVars tv;
-    int id;
-
     memset(&tv, 0, sizeof(ThreadVars));
-
+    int id = RegisterCounter("t1", "c1", &tv.perf_public_ctx);
-    id = RegisterCounter("t1", "c1", &tv.perf_public_ctx);
     FAIL_IF(id != 1);
-
     int r = StatsGetAllCountersArray(NULL, &tv.perf_private_ctx);
     FAIL_IF_NOT(r == -1);
+    StatsReleaseCounters(tv.perf_public_ctx.head);
+    StatsReleasePrivateThreadContext(&tv.perf_private_ctx);
     PASS;
 }