8240347: remove undocumented options from jlink --help message

Reviewed-by: alanb, redestad
diff --git a/src/jdk.jlink/share/classes/jdk/tools/jlink/internal/TaskHelper.java b/src/jdk.jlink/share/classes/jdk/tools/jlink/internal/TaskHelper.java
index 229076c..3c74944 100644
--- a/src/jdk.jlink/share/classes/jdk/tools/jlink/internal/TaskHelper.java
+++ b/src/jdk.jlink/share/classes/jdk/tools/jlink/internal/TaskHelper.java
@@ -129,7 +129,7 @@
                       String shortname,
                       boolean isTerminal)
         {
-            this(hasArg, processing, false, name, shortname, "", isTerminal);
+            this(hasArg, processing, hidden, name, shortname, "", isTerminal);
         }
 
         public Option(boolean hasArg, Processing<T> processing, String name, String shortname, boolean isTerminal) {