Attach (recommended) or Link to PDF file here:
[backgroundimage_not_visible_anonymisiert.pdf](https://github.com/mozilla/pdf.js/files/6544725/backgroundimage_not_visible_anonymisiert.pdf)


Configuration:
- Web browser and its version: Chrome Version 90.0.4430.212 (Offizieller Build) (x86_64)
- Operating system and its version: Windows 10, MacOs BigSur
- PDF.js version: 2.5.207
- Is a browser extension: no

Steps to reproduce the problem:
1. open the document in demo viewer.js
2.

What is the expected behavior? (add screenshot)
The backgroundimage gets rendered like in Acrobat Reader
<img width="1348" alt="Bildschirmfoto 2021-05-26 um 09 44 21" src="https://user-images.githubusercontent.com/1286150/119621970-00a82480-be07-11eb-8fed-f74ac04b840b.png">

What went wrong? (add screenshot)
Backgroundimage is not rendered only some  text
<img width="987" alt="Bildschirmfoto 2021-05-26 um 09 43 57" src="https://user-images.githubusercontent.com/1286150/119621938-fab24380-be06-11eb-92ac-4ecb2c9334b1.png">




Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):

type = pp;
        
        points[p] = 0;
      } else {
        
        
        type = pp & ((0x33 * type) >> 4);
        
        points[p] &= (type >> 2) | (type << 2);
      }
      coords.push(p % width1, (p / width1) | 0);
      if (!points[p]) {
        --count;
      }
    } while (p0 !== p);
    outlines.push(coords);
    --i;
  }
  const drawOutline = function (c) {
    c.save();
    
    c.scale(1 / width, -1 / height);
    c.translate(0, -height);
    c.beginPath();
    for (let k = 0, kk = outlines.length; k < kk; k++) {
      const o = outlines[k];
      c.moveTo(o[0], o[1]);
      for (let l = 2, ll = o.length; l < ll; l += 2) {
        c.lineTo(o[l], o[l + 1]);