Redirect dupsigs test output to proper logger

Ensure messages from dupsigs system test end up in its log rather than
stdout. Previously, the output was hard to debug when running the tests
in parallel and messages wouldn't end up in the dupsigs.log.

(cherry picked from commit cbe2559f37)

bin/tests/system/dupsigs/tests.sh

@@ -39,10 +39,10 @@ end=$((start + 140))
 
 while [ $now -lt $end ]; do
         et=$((now - start))
-	echo "=============== $et ============"
-	$JOURNALPRINT ns1/signing.test.db.signed.jnl | $PERL check_journal.pl
+	echo_i "............... $et ............"
+	$JOURNALPRINT ns1/signing.test.db.signed.jnl | $PERL check_journal.pl | cat_i
 	$DIG axfr signing.test -p ${PORT} @10.53.0.1 > dig.out.at$et
-	awk '$4 == "RRSIG" { print $11 }' dig.out.at$et | sort | uniq -c
+	awk '$4 == "RRSIG" { print $11 }' dig.out.at$et | sort | uniq -c | cat_i
 	lines=`awk '$4 == "RRSIG" { print}' dig.out.at$et | wc -l`
 	if [ ${et} -ne 0 -a ${lines} -ne 1009 ]
 	then