tdf#120865: preserve cursor shape on repositioning the cursor

i.e. don't recreate cursor with new (default) arrow shape in
SalFrame::SetPointerPos, but simply move the existing one

Change-Id: I3406ceff25a53de6f2afa318114370c318e6a500
Reviewed-on: https://gerrit.libreoffice.org/70049
Tested-by: Jenkins
Reviewed-by: Katarina Behrens <Katarina.Behrens@cib.de>

vcl/qt5/Qt5Frame.cxx

@@ -687,9 +687,9 @@ void Qt5Frame::CaptureMouse(bool bMouse)
 
 void Qt5Frame::SetPointerPos(long nX, long nY)
 {
-    QCursor aCursor = m_pQWidget->cursor();
+    // some cursor already exists (and it has m_ePointerStyle shape)
+    // so here we just reposition it
     QCursor::setPos(m_pQWidget->mapToGlobal(QPoint(nX, nY)));
-    m_pQWidget->setCursor(aCursor);
 }
 
 void Qt5Frame::Flush()