EditorManager: Update current editor prior to deleting other editors

Otherwise it may happen that destructor of an editor being
deleted may trigger a call to EditorManager::currentEditor()
before reaching the editor's QObject destructor. In this case
the pointer to the editor (EditorManagerPrivate::m_currentEditor)
isn't cleared yet by Qt and it may return the pointer to
partially destructed object.

Change-Id: I4f44dce8d680008148a73eb2a8ac13477d0fb825
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/coreplugin/editormanager/editormanager.cpp

@@ -1751,9 +1751,6 @@ bool EditorManagerPrivate::closeEditors(const QList<IEditor*> &editors, CloseFla
 
     emit m_instance->editorsClosed(Utils::toList(acceptedEditors));
 
-    foreach (IEditor *editor, acceptedEditors)
-        delete editor;
-
     if (focusView) {
         activateView(focusView);
     } else {
@@ -1761,6 +1758,9 @@ bool EditorManagerPrivate::closeEditors(const QList<IEditor*> &editors, CloseFla
         setCurrentEditor(currentView->currentEditor());
     }
 
+    foreach (IEditor *editor, acceptedEditors)
+        delete editor;
+
     if (!EditorManager::currentEditor()) {
         emit m_instance->currentEditorChanged(nullptr);
         updateActions();