Fix an race condition in the auto test.

Deleting the page in the wizard without removing it
first leads to a crash when the wizard tries to
access a deleted page.

Reviewed-by: jasplin
(cherry picked from commit 3bff1637cd49617d334c1be63c20e008fac93be1)

tests/auto/qwizard/tst_qwizard.cpp

@@ -1770,8 +1770,11 @@ public:
 
     ~TestWizard()
     {
-        foreach (int id, pageIds)
-            delete page(id);
+        foreach (int id, pageIds) {
+            QWizardPage *page_to_delete = page(id);
+            removePage(id);
+            delete page_to_delete;
+	}
     }
 
     void applyOperations(const QList<Operation *> &operations)