Attach (recommended) or Link to PDF file here:
PDF from #4106, https://mail.gnome.org/archives/evince-list/2013-November/pdfNC0hkVW67a.pdf.

Steps to reproduce the problem:
1. Open the PDF

What is the expected behavior?
![immagine](https://user-images.githubusercontent.com/1616846/121865567-67ca4200-ccfe-11eb-8673-1d6e863fc8d5.png)

What went wrong?
The PDF doesn't load, `TypeError: can't access property Symbol(), match is null` error is logged in the console.
style.height = measureToString(this.medium.long);
      if (this.medium.orientation === "landscape") {
        const x = style.width;
        style.width = style.height;
        style.height = x;
      }
    } else {
      warn("XFA - No medium specified in pageArea: please file a bug.");
    }
    this[$childrenToHTML]({
      filter: new Set(["area", "draw", "field", "subform"]),
      include: true,
    });
    
    
    this[$childrenToHTML]({
      filter: new Set(["contentArea"]),
      include: true,
    });
    return HTMLResult.success({
      name: "div",
      children,
      attributes: {
        id: this[$uid],
        style,
      },
    });
  }
}
class PageSet extends XFAObject {