8203463: [Accessibility, Narrator] NPE in TableView

Backport-of: c705bd493931d88650542be5466d6add359f45b9

Author: Johan Vos

modules/javafx.graphics/src/main/java/com/sun/glass/ui/win/WinAccessible.java

@@ -565,6 +565,7 @@ private void changeSelection(boolean add, boolean clear) {
     private long GetPatternProvider(int patternId) {
         if (isDisposed()) return 0;
         AccessibleRole role = (AccessibleRole)getAttribute(ROLE);
+        if (role == null) return 0;
         boolean impl = false;
         switch (role) {
             case MENU: