[skip ci]Add comment fo ci_util script (#12125)

Signed-off-by: NJenny Li <jing.li@zilliz.com>

tests/scripts/ci-util.sh

@@ -14,6 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# Exit immediately for non zero status
 set -e
 set -u
 set -x