Fixes #4792. Unhandled Java exception in Ripper on inline comments.

We assumed all delayed token dispatches would have a valid delayed and we NPE
when we dup'd our ByteList.  MRI does not use an object like us and 0/NULL
ends up being nil.  Added simple check for null since we have no similar magic.

core/src/main/java/org/jruby/ext/ripper/RipperLexer.java

@@ -762,11 +762,10 @@ public void dispatchDelayedToken(int token) { //mri: rupper_dispatch_delayed_tok
 
         ruby_sourceline = delayed_line;
         tokp = lex_pbeg + delayed_col;
-
-        //System.out.println("TOKP: " + tokp + ", LEX_P: " + lex_p);        
-        IRubyObject value = parser.getRuntime().newString(delayed.dup());
+
         String event = tokenToEventId(token);
-        //System.out.println("EVENT: " + event + ", VALUE: " + value);
+        IRubyObject value = delayed == null ? parser.context.nil : parser.getRuntime().newString(delayed.dup());
+
         yaccValue = parser.dispatch(event, value);
         delayed = null;
         ruby_sourceline = saved_line;