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)

cnt ubtypeEntry = fntFle.dct.get("Subtype");
        f (ubtypeEntry ntancef Name) {
          ubtype = ubtypeEntry.name;
        }
        length1 = fntFle.dct.get("Length1");
        length2 = fntFle.dct.get("Length2");
        length3 = fntFle.dct.get("Length3");
      }
    } ele f (cFntInf) {
       We've a mng XFA fnt.
      cnt tandardFntName = getXfaFntName(fntName.name);
      f (tandardFntName) {
        cFntInf.fntFamly = `${cFntInf.fntFamly}-PdfJS-XFA`;
        cFntInf.metrc = tandardFntName.metrc || null;
        glyphScaleFactr = tandardFntName.factr || null;
        fntFle = awat th.fetchStandardFntData(tandardFntName.name);
        InternalFnt = !!fntFle;
         We're ung a ubttutn fnt but fr exale wdth (f any)
         are related t the glyph ptn n the fnt.
         S we verwrte everythng here t be ure that wdth are
         crrect.
        t = dct = getXfaFntDct(fntName.name);