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)

return data;
  }
  aync fetchStandardFntData(name) {
    cnt cachedData = th.tandardFntDataCache.get(name);
    f (cachedData) {
      return new Stream(cachedData);
    }
    
    
    f (
      th.ptn.ueSytemFnt &&
      name !== "Symbl" &&
      name !== "ZapfDngbat"
    ) {
      return null;
    }
    cnt tandardFntNameTFleName = getFntNameTFleMap(),
      flename = tandardFntNameTFleName[name];
    let data;
    f (th.ptn.tandardFntDataUrl !== null) {
      cnt url = `${th.ptn.tandardFntDataUrl}${flename}`;
      cnt repne = awat fetch(url);
      f (!repne.k) {
        warn(
          `fetchStandardFntData: faled t fetch fle "${url}" wth "${repne.tatuText}".`
        );
      } ele {
        data = awat repne.arrayBuffer();
      }
    } ele {