Attach (recommended) or Link to PDF file here:
[imm5710f(1).pdf](https://github.com/mozilla/pdf.js/files/6924738/imm5710f.1.pdf)

Configuration:
- Web browser and its version: Firefox nightly
- Operating system and its version: Debian

Steps to reproduce the problem:
1. Open the pdf on page 3 
2. See the 2 fields after `DÉTAILS DU TRAVAIL PRÉVU AU CANADA`

What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/5641725/128031365-84b17d62-f805-43d1-9d05-e2b535efa3ef.png)

const extra = node[$extra];
  const availableSpace = extra.availableSpace;
  const [x, y, w, h] = bbox;
  switch (node.layout) {
    case "position": {
      extra.width = Math.max(extra.width, x + w);
      extra.height = Math.max(extra.height, y + h);
      extra.children.push(html);
      break;
    }
    case "lr-tb":
    case "rl-tb":
      if (!extra.line || extra.attempt === 1) {
        extra.line = createLine(node, []);
        extra.children.push(extra.line);
        extra.numberInLine = 0;
      }
      extra.numberInLine += 1;
      extra.line.children.push(html);
      if (extra.attempt === 0) {
        
        extra.currentWidth += w;
        extra.height = Math.max(extra.height, extra.prevHeight + h);
      } else {
        extra.currentWidth = w;
        extra.prevHeight = extra.height;
        extra.height += h;