QQuickItemView::currentItemChanged called upon currentItem destruction

There were some cases where the signal wasn't emitted and we ended up
with events being delivered to objects that didn't exist anymore.

Task-number: QTBUG-65881
Change-Id: I847669a978e82a0332907b029a8295bb993d2850
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@qt.io>

src/quick/items/qquickitemview.cpp

@@ -1750,6 +1750,7 @@ void QQuickItemViewPrivate::updateCurrent(int modelIndex)
 
 void QQuickItemViewPrivate::clear()
 {
+    Q_Q(QQuickItemView);
     currentChanges.reset();
     bufferedChanges.reset();
     timeline.clear();
@@ -1763,8 +1764,11 @@ void QQuickItemViewPrivate::clear()
     }
     releasePendingTransition.clear();
 
+    auto oldCurrentItem = currentItem;
     releaseItem(currentItem);
     currentItem = 0;
+    if (oldCurrentItem)
+        emit q->currentItemChanged();
     createHighlight();
     trackedItem = 0;
 
@@ -2120,8 +2124,11 @@ bool QQuickItemViewPrivate::applyModelChanges(ChangeResult *totalInsertionResult
         if (currentChanges.currentRemoved && currentItem) {
             if (currentItem->item && currentItem->attached)
                 currentItem->attached->setIsCurrentItem(false);
+            auto oldCurrentItem = currentItem;
             releaseItem(currentItem);
             currentItem = 0;
+            if (oldCurrentItem)
+                emit q->currentItemChanged();
         }
         if (!currentIndexCleared)
             updateCurrent(currentChanges.newCurrentIndex);