core/window: backing windows can now be destroyed and recreated

This fixes a crash in layershells and the setVisible crash on nvidia.

src/core/test/CMakeLists.txt

@@ -1,15 +1,7 @@
 function (qs_test name)
 	add_executable(${name} ${ARGN})
-	target_link_libraries(${name} PRIVATE ${QT_DEPS} Qt6::Test)
+	target_link_libraries(${name} PRIVATE ${QT_DEPS} Qt6::Test quickshell-core)
 	add_test(NAME ${name} WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}" COMMAND $<TARGET_FILE:${name}>)
 endfunction()
 
-qs_test(popupwindow
-	popupwindow.cpp
-	../popupwindow.cpp
-	../proxywindow.cpp
-	../qmlscreen.cpp
-	../region.cpp
-	../reload.cpp
-	../windowinterface.cpp
-)
+qs_test(popupwindow popupwindow.cpp)

src/core/test/popupwindow.cpp

@@ -1,6 +1,5 @@
 #include "popupwindow.hpp"
 
-#include <qlogging.h>
 #include <qquickwindow.h>
 #include <qsignalspy.h>
 #include <qtest.h>
@@ -52,7 +51,6 @@ void TestPopupWindow::reloadReparent() { // NOLINT
 
 	auto spy = QSignalSpy(oldWindow, &QWindow::visibleChanged);
 
-	qDebug() << "reload";
 	newParent.onReload(&parent);
 	newPopup.onReload(&popup);