Fixed: command line testing with Javac9+ would fail on all tests that are testing that the compiler emits warning/error messages.

src/delombok/lombok/delombok/Delombok.java

@@ -527,6 +527,7 @@ public class Delombok {
 			}
 			String[] argv = argsList.toArray(new String[0]);
 			args.init("javac", argv);
+			options.put("diags.legacy", "TRUE");
 		}
 		
 		CommentCatcher catcher = CommentCatcher.create(context);