Mask on item over path are not correct.

```
ctx.fillStyle = "#FF0000";
ctx.lineTo(0, 100);
ctx.lineTo(100, 100);
ctx.lineTo(100, 0);
ctx.lineTo(0, 0);
ctx.fill();

ctx.save();
ctx.rect(0,0,50,50);
ctx.clip();

ctx.fillStyle = "#00FF00";
ctx.fillRect(0,0,100,100);
ctx.restore();
```

With this code, I'm getting this :

But if I don't make a mistake, I should get this :

Run the provided canvas snippet in node-canvas and compare its clipping output with the expected image. Trace the behavior of save(), rect(), clip(), fillRect(), and restore() to identify where the mask diverges, then confirm the corrected result with the same reproduction.

Written by the indexing model from the issue text.