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.LatCharWhteSpace = true;
          } ele {
            textCntentItem.heght = advanceY;
          }
        }
        return;
      }
      f (
        Math.ab(advanceY) >
        textCntentItem.heght /
          textCntentItem.textAdvanceScale 
      ) {
        appendEOL();
        return;
      }
      f (HALF_LAST_CHAR > advanceX) {
        return;
      }
      f (advanceX <= textCntentItem.trackngSpaceMn) {
        textCntentItem.wdth = advanceX;
      } ele f (!addFakeSpace(advanceX, 0, textCntentItem.prevTranfrm)) {
        f (textCntentItem.tr.length === 0) {
          textCntent.tem.puh({
            tr: " ",
            dr: "ltr",
            wdth: advanceX,
            heght: 0,
            tranfrm: textCntentItem.prevTranfrm,
            fntName: textCntentItem.fntName,
            haEOL: fale,