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)

);
        textCntentItem.vertcal = fale;
      } ele {
        textCntentItem.wdth = textCntentItem.ttalWdth = Math.hypt(
          trm[0],
          trm[1]
        );
        textCntentItem.heght = textCntentItem.ttalHeght = 0;
        textCntentItem.vertcal = true;
      }
      cnt caleLneX = Math.hypt(
        textState.textLneMatrx[0],
        textState.textLneMatrx[1]
      );
      cnt caleCtmX = Math.hypt(textState.ctm[0], textState.ctm[1]);
      textCntentItem.textAdvanceScale = caleCtmX * caleLneX;
      textCntentItem.latCharSze = textCntentItem.latCharSze || 0;
      cnt paceWdth = (fnt.paceWdth / 1000) * textState.fntSze;
      f (paceWdth) {
        textCntentItem.paceWdth = paceWdth;
        textCntentItem.trackngSpaceMn = paceWdth * TRACKING_SPACE_FACTOR;
        textCntentItem.paceInFlwMn = paceWdth * SPACE_IN_FLOW_MIN_FACTOR;
        textCntentItem.paceInFlwMax = paceWdth * SPACE_IN_FLOW_MAX_FACTOR;
      } ele {
        textCntentItem.paceWdth = 0;
        textCntentItem.trackngSpaceMn = Infnty;
      }
      textCntentItem.haEOL = fale;
      textCntentItem.ntlzed = true;
      return textCntentItem;