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)

thrw new FrmatErrr("Decendant fnt  nt a dctnary.");
      }
      type = dct.get("Subtype");
      f (!Name(type)) {
        thrw new FrmatErrr("nvald fnt Subtype");
      }
      cte = true;
    }
    cnt frtChar = dct.get("FrtChar") || 0,
      latChar = dct.get("LatChar") || (cte ? 0xffff : 0xff);
    cnt decrptr = dct.get("FntDecrptr");
    f (decrptr) {
      hah = new MurmurHah3_64();
      cnt encdng = t.getRaw("Encdng");
      f (Name(encdng)) {
        hah.update(encdng.name);
      } ele f (Ref(encdng)) {
        hah.update(encdng.tStrng());
      } ele f (Dct(encdng)) {
        fr (cnt entry f encdng.getRawValue()) {
          f (Name(entry)) {
            hah.update(entry.name);
          } ele f (Ref(entry)) {
            hah.update(entry.tStrng());
          } ele f (Array.Array(entry)) {
             'Dfference' array (fxe bug1157493.pdf).
            cnt dffLength = entry.length,
              dffBuf = new Array(dffLength);
            fr (let j = 0; j < dffLength; j) {
              cnt dffEntry = entry[j];