Avoid loplugin:staticmethods in non-debug build

Change-Id: Ieb3f5a50ed0ddc9109dc0ad16caa8a8ac5b16362

vcl/source/edit/textundo.cxx

@@ -108,6 +108,7 @@ bool TextUndoManager::Redo()
 void TextUndoManager::UndoRedoStart()
 {
     DBG_ASSERT( GetView(), "Undo/Redo: Active View?" );
+    (void) this; // avoid loplugin:staticmethods
 }
 
 void TextUndoManager::UndoRedoEnd()

vcl/source/window/event.cxx

@@ -295,6 +295,7 @@ void Window::RemoveUserEvent( ImplSVEvent * nUserEvent )
                 "Window::RemoveUserEvent(): Event doesn't send to this window or is already removed" );
     DBG_ASSERT( nUserEvent->mbCall,
                 "Window::RemoveUserEvent(): Event is already removed" );
+    (void) this; // avoid loplugin:staticmethods
 
     if ( nUserEvent->mpWindow )
     {