tdf#53282: Leave (our own) full-screen mode when the AquaSalFrame is dying

Change-Id: I85243dff96b9090de0fd55564b44abb6142d9ac2
Reviewed-on: https://gerrit.libreoffice.org/56524
Tested-by: Jenkins
Reviewed-by: Tor Lillqvist <tml@collabora.com>

vcl/osx/salframe.cxx

@@ -92,6 +92,9 @@ AquaSalFrame::AquaSalFrame( SalFrame* pParent, SalFrameStyleFlags salFrameStyle
 
 AquaSalFrame::~AquaSalFrame()
 {
+    if (mbFullScreen)
+        ShowFullScreen(false, maGeometry.nDisplayScreenNumber);
+
     assert( GetSalData()->mpInstance->IsMainThread() );
 
     // if the frame is destroyed and has the current menubar