`EventResult::Exit` is hit before `Event::LoopDestroyed` is, and due to
possibly some order of operations or drops the window is never destroyed
on Linux. Adding a call to `winit_app.save_and_destroy();` where
`EventResult::Exit` is checked solves this.
Closes#2892
Signed-off-by: Luke D. Jones <luke@ljones.dev>
7c12bb692b