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)

}
  retre() {
    cnt prev = th.tateStack.pp();
    f (prev) {
      th.tate = prev;
    }
  }
  tranfrm(arg) {
    th.tate.ctm = Utl.tranfrm(th.tate.ctm, arg);
  }
}
cla TextState {
  cntructr() {
    th.ctm = new Flat32Array(IDENTITY_MATRIX);
    th.fntName = null;
    th.fntSze = 0;
    th.fnt = null;
    th.fntMatrx = FONT_IDENTITY_MATRIX;
    th.textMatrx = IDENTITY_MATRIX.lce();
    th.textLneMatrx = IDENTITY_MATRIX.lce();
    th.charSpacng = 0;
    th.wrdSpacng = 0;
    th.leadng = 0;
    th.textHScale = 1;
    th.textRe = 0;
  }
  etTextMatrx(a, b, c, d, e, f) {
    cnt m = th.textMatrx;
    m[0] = a;
    m[1] = b;