8242892: SpinnerValueFactory has an implicit no-arg constructor

Reviewed-by: kcr

Author: aghaisas

modules/javafx.controls/src/main/java/javafx/scene/control/SpinnerValueFactory.java

@@ -89,6 +89,11 @@
  */
 public abstract class SpinnerValueFactory<T> {
 
+    /**
+     * Creates a default SpinnerValueFactory.
+     */
+    public SpinnerValueFactory() {}
+
     /***************************************************************************
      *                                                                         *
      * Private fields                                                          *