Windows: QMimeData::retrieveData() on mime data set on the clipboard is called after destruction of Q[Gui]Application, causing problems when setting QPixmap/QImage data

Steps to reproduce (qtbug36958.zip):

• Launch app, press "Copy Custom Mime DAta"
• Quit
  Note assert:

  MyDialog::MyDialog
  MyMimeData::MyMimeData
  MyDialog::slotCopyCustomMimeData QMimeData(0x5c032f0590)
  MyMimeData::formats ("application/x-qt-image")
  MyMimeData::retrieveData "application/x-qt-image" QVariant::QImage
  MyMimeData::retrieveData returns QVariant(QPixmap, QPixmap(QSize(32, 32) )  )
  MyMimeData::formats ("application/x-qt-image")
  MyDialog::~MyDialog
  MyMimeData::formats ("application/x-qt-image")
  MyMimeData::retrieveData "application/x-qt-image" QVariant::QImage
  QCoreApplication::arguments: Please instantiate the QApplication object first
  QPixmap: Must construct a QGuiApplication before a QPixmap
  

  Same problem exists in Qt 4, but it does not crash.