Cache tagging hintkey

DEVSIX-8836

Author: guustysebie

layout/src/main/java/com/itextpdf/layout/tagging/LayoutTaggingHelper.java

@@ -685,7 +685,7 @@ private int getNearestNextSiblingTagIndex(WaitingTagsManager waitingTagsManager,
     }
 
     private static boolean isNonAccessibleHint(TaggingHintKey hintKey) {
-        return hintKey.getAccessibleElement() == null || hintKey.getAccessibleElement().getAccessibilityProperties().getRole() == null;
+        return !hintKey.isAccessible();
     }
 
     private boolean isTagAlreadyExistsForHint(TaggingHintKey tagHint) {

layout/src/main/java/com/itextpdf/layout/tagging/TaggingHintKey.java

@@ -39,6 +39,7 @@ public final class TaggingHintKey {
     private String overriddenRole;
     private boolean elementBasedFinishingOnly;
     private  TagTreePointer tagPointer;
+    private final boolean isAccessible;
 
     /**
      * Instantiate a new {@link TaggingHintKey} instance.
@@ -49,6 +50,11 @@ public final class TaggingHintKey {
     TaggingHintKey(IAccessibleElement elem, boolean createdElementBased) {
         this.elem = elem;
         this.elementBasedFinishingOnly = createdElementBased;
+        if (elem == null){
+            isAccessible = false;
+        }else{
+            isAccessible = elem.getAccessibilityProperties().getRole() != null;
+        }
     }
 
     /**
@@ -143,4 +149,8 @@ void setOverriddenRole(String overriddenRole) {
     boolean isElementBasedFinishingOnly() {
         return elementBasedFinishingOnly;
     }
+
+    boolean isAccessible() {
+        return isAccessible;
+    }
 }