Editors: Fix soft assert about empty currentView

We need to always either have a current view or a current editor.
Make sure we set the current view if we end up without a current
editor when closing files.

Amends ee1e6ca508

Fixes: QTCREATORBUG-24869
Change-Id: I9e1982697700079e037695e100ef71eadaf7849f
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/coreplugin/editormanager/editormanager.cpp

@@ -1743,10 +1743,12 @@ bool EditorManagerPrivate::closeEditors(const QList<IEditor*> &editors, CloseFla
     foreach (IEditor *editor, acceptedEditors)
         delete editor;
 
-    if (focusView)
+    if (focusView) {
         activateView(focusView);
-    else
+    } else {
+        setCurrentView(currentView);
         setCurrentEditor(currentView->currentEditor());
+    }
 
     if (!EditorManager::currentEditor()) {
         emit m_instance->currentEditorChanged(nullptr);