Further numerical robustness issue in path rendering

[ChengCat]

Hello, I've quietly followed this project for quite some time, and thank you for this great work!

I am aware the path rendering algorithm is numerically tricky, and many numeric issues have already been resolved in the past. But unfortunately I still run into one issue here. The following incorrectly rendered image is produced by latest vello on the main branch (8a84a4a); the correct image should be a white filled square.

To reproduce, replace the function add_shapes_to_scene in examples/simple/src/main.rs with the following code:

fn add_shapes_to_scene(scene: &mut Scene) {
    use vello::kurbo::PathEl::*;

    let path = [
        MoveTo((0.0, 0.0).into()),
        LineTo((1000., 0.).into()),
        LineTo((1000., 1000.).into()),
        LineTo((0., 1000.).into()),
        LineTo((-1.87016292e-06, 923.848633).into()),
        LineTo((1.87016292e-06, 156.151367).into()),
        ClosePath,
    ];

    scene.fill(
        vello::peniko::Fill::NonZero,
        Affine::IDENTITY,
        Color::new([1.,1.,1.,1.]),
        None,
        &path,
    );
}