This is a regression from PR #4615. The underscore for the last 2 chars in "NUMERO D’IMMATRICULATION" is too bold.

URL: http://www.ameli.fr/fileadmin/user_upload/formulaires/S3706.pdf
1.1.215: https://i.imgur.com/up8Y33j.png
0.8.990: https://i.imgur.com/UioZcLB.png

fc1e2483b433134a538cce0acd0ccc76e335cf5f is the first bad commit
commit fc1e2483b433134a538cce0acd0ccc76e335cf5f
Author: Jonas Jenwald
Date:   Fri Apr 11 20:19:39 2014 +0200

```
Enforce minimum line widths
```

ctx.strokeStyle = "#000000";
    ctx.fillStyle = "#000000";
    ctx.fillRule = "nonzero";
    ctx.globalAlpha = 1;
    ctx.lineWidth = 1;
    ctx.lineCap = "butt";
    ctx.lineJoin = "miter";
    ctx.miterLimit = 10;
    ctx.globalCompositeOperation = "source-over";
    ctx.font = "10px sans-serif";
    if (ctx.setLineDash !== undefined) {
      ctx.setLineDash([]);
      ctx.lineDashOffset = 0;
    }
  }
  function composeSMaskBackdrop(bytes, r0, g0, b0) {