tst_popup.qml::test_popupWithOverlayInLoader() crash

Run the test: tst_popup.qml::test_popupWithOverlayInLoader(), adding "popupType: Popup.Window".
The test crashes when deactivating the loader. The global position is trying to be calculated despite the parent window being set to null in deactivation.

Test output:

PASS   : tst_controls::Universal::Popup::initTestCase()
Received signal 11 (SIGSEGV), code 1, for address 0x0000000000000008
         Popup::test_popupWithOverlayInLoader function time: 27ms, total time: 30ms