suppress errors on new 2-pass and 3-pass ipro tests

test/nginx_system_test.sh

@@ -308,6 +308,8 @@ STATISTICS_URL=http://$PRIMARY_HOSTNAME/ngx_pagespeed_statistics
 # An expected failure can be indicated like: "~In-place resource optimization~"
 PAGESPEED_EXPECTED_FAILURES="
 ~Cache purging with PageSpeed off in vhost, but on in directory.~
+~2-pass ipro with long ModPagespeedInPlaceRewriteDeadline~
+~3-pass ipro with short ModPagespeedInPlaceRewriteDeadline~
 "
 
 if [ "$POSITION_AUX" = "true" ] ; then