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)

width: availableSpace.width - marginH,
        height: availableSpace.height - marginV - node[$extra].height,
      };
    case "rl-row":
    case "row":
      const width = node[$extra].columnWidths
        .slice(node[$extra].currentColumn)
        .reduce((a, x) => a + x);
      return { width, height: availableSpace.height - marginH };
    case "table":
    case "tb":
      return {
        width: availableSpace.width - marginH,
        height: availableSpace.height - marginV - node[$extra].height,
      };
    case "position":
    default:
      return availableSpace;
  }
}
function getTransformedBBox(node) {
  
  let w = node.w === "" ? NaN : node.w;
  let h = node.h === "" ? NaN : node.h;
  let [centerX, centerY] = [0, 0];
  switch (node.anchorType || "") {
    case "bottomCenter":
      [centerX, centerY] = [w / 2, h];
      break;
    case "bottomLeft":