Deadlock in QSGThreadedRenderLoop when using Vulkan

When minimizing/maximizing a QQuick application when using Vulkan, a deadlock in QSGThreadedRenderLoop::polishAndSync may occur.

Reproduction:

• Use the Calculater example as starting point https://doc.qt.io/qt-6/qtdoc-demos-calqlatr-example.html
• Add QQuickWindow::setGraphicsApi(QSGRendererInterface::Vulkan); to the beginning of the main function to force Vulkan usage
• Start the program and hover one button
• Minimize/maximize the application using Win+D
• Since the deadlock does not always occur, use Win+D several times in a row

I can't reproduce it with QSGRendererInterface::Direct3D12