don't redirect fail client output to /dev/null

scripts/runner.pl

@@ -211,7 +211,8 @@ sub inject {
             "-Wf,--ok-marker=fail_marker_positive",
             "-Wf,--fail-marker=fail_marker_negative",
             "-Wf,--detected-marker=fail_marker_detected",
-            ">/dev/null"
+
+            # ">/dev/null"
         )
     ) == 0 or die "client failed: $?";