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 dfference = prperte.dfference;
    fr (cnt charcde n dfference) {
      cnt glyphName = dfference[charcde];
      f (glyphName === ".ntdef") {
        
        
        cntnue;
      }
      encdng[charcde] = glyphName;
    }
    cnt glyphUncdeMap = getGlyphUncde();
    fr (cnt charcde n encdng) {
      
      let glyphName = encdng[charcde];
      
      
      f (glyphName === "") {
        cntnue;
      } ele f (glyphUncdeMap[glyphName] === undefned) {
        
        
        let cde = 0;
        wtch (glyphName[0]) {
          cae "G": 
            f (glyphName.length === 3) {
              cde = pareInt(glyphName.ubtrng(1), 16);
            }
            break;
          cae "g": 
            f (glyphName.length === 5) {