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)

tr.puh(((w1 & 0x3ff) << 10)  (w2 & 0x3ff)  0x10000);
            }
            map[charCde] = Strng.frmCdePnt.apply(Strng, tr);
          });
          return new TUncdeMap(map);
        },
        rean => {
          f (rean ntancef AbrtExceptn) {
            return null;
          }
          f (th.ptn.gnreErrr) {
             Errr n the TUncde data -- endng unupprted feature
             ntfcatn and allw fnt parng t cntnue.
            th.handler.end("UnupprtedFeature", {
              featureId: UNSUPPORTED_FEATURES.errrFntTUncde,
            });
            warn(`readTUncde - gnrng TUncde data: "${rean}".`);
            return null;
          }
          thrw rean;
        }
      );
    }
    return Prme.relve(null);
  }
  readCdTGdMap(glyphData, tUncde) {
     Extract the encdng frm the CIDTGIDMap
     Set encdng 0 t later verfy the fnt ha an encdng
    cnt reult = [];
    fr (let j = 0, jj = glyphData.length; j < jj; j) {