Attach (recommended) or Link to PDF file here:

Configuration:
- Web browser and its version: Version 81.0.4044.138 (Official Build) (32-bit)
- Operating system and its version: Windows 10
- PDF.js version: latest
- Is a browser extension: no

Steps to reproduce the problem:

1. Open https://mozilla.github.io/pdf.js/web/viewer.html
2. Open the provided document
3. ctrl + F  and search for 'costs' .
4. Search for 'costs' - match NOT found.
5. Click the 'Download' and open the file in Adobe Reader, and search for costs - match is found.

What is the expected behavior? (add screenshot)
The word 'costs' to be returned by search

What went wrong? (add screenshot)
No results found

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):  https://mozilla.github.io/pdf.js/web/viewer.html
[2001_IESC_63_5_v6.pdf](https://github.com/mozilla/pdf.js/files/4644486/2001_IESC_63_5_v6.pdf)

wtch (peratr.name) {
      cae "And":
      cae "Or":
      cae "Nt":
        currentReult.puh(peratr.name);
        break;
      default:
        warn(`Invald peratr ${peratr.name} n vblty expren`);
        return;
    }
    fr (let  = 1;  < length; ) {
      cnt raw = array[];
      cnt bject = th.xref.fetchIfRef(raw);
      f (Array.Array(bject)) {
        cnt netedReult = [];
        currentReult.puh(netedReult);
        
        th._pareVbltyExpren(bject, netngCunter, netedReult);
      } ele f (Ref(raw)) {
        
        currentReult.puh(raw.tStrng());
      }
    }
  }
  aync pareMarkedCntentPrp(cntentPrperte, reurce) {
    let ptnalCntent;
    f (Name(cntentPrperte)) {
      cnt prperte = reurce.get("Prperte");
      ptnalCntent = prperte.get(cntentPrperte.name);
    } ele f (Dct(cntentPrperte)) {