Remove leftover test development echo

(cherry picked from commit 1a82a1999b)

bin/tests/system/checkzone/tests.sh

@@ -207,7 +207,6 @@ ret=0
 echo_i "checking integer overflow is prevented in \$GENERATE ($n)"
 $CHECKZONE -D example.com zones/generate-overflow.db >test.out.$n 2>&1 || ret=1
 lines=$(grep -c CNAME test.out.$n)
-echo $lines
 [ "$lines" -eq 1 ] || ret=1
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=$((status + ret))