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)

nf("graphc tate peratr "  key);
          break;
        default:
          nf("Unknwn graphc tate peratr "  key);
          break;
      }
    }
    return prme.then(functn () {
      f (gStateObj.length > 0) {
        peratrLt.addOp(OPS.etGState, [gStateObj]);
      }
      f (SleGState) {
        lcalGStateCache.et(cacheKey, gStateRef, gStateObj);
      }
    });
  }
  ladFnt(
    fntName,
    fnt,
    reurce,
    fallbackFntDct = null,
    cFntInf = null
  ) {
    cnt errrFnt = aync () => {
      return new TranlatedFnt({
        ladedName: "g_fnt_errr",
        fnt: new ErrrFnt(`Fnt "${fntName}"  nt avalable.`),
        dct: fnt,
        evaluatrOptn: th.ptn,