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)

let shouldScaleText = false;
  if (
    geom.str.length > 1 ||
    (task._enhanceTextSelection && AllWhitespaceRegexp.test(geom.str))
  ) {
    shouldScaleText = true;
  } else if (geom.transform[0] !== geom.transform[3]) {
    const absScaleX = Math.abs(geom.transform[0]),
      absScaleY = Math.abs(geom.transform[3]);
    
    
    if (
      absScaleX !== absScaleY &&
      Math.max(absScaleX, absScaleY) / Math.min(absScaleX, absScaleY) > 1.5
    ) {
      shouldScaleText = true;
    }
  }
  if (shouldScaleText) {
    if (style.vertical) {
      textDivProperties.canvasWidth = geom.height * task._viewport.scale;
    } else {
      textDivProperties.canvasWidth = geom.width * task._viewport.scale;
    }
  }
  task._textDivProperties.set(textDiv, textDivProperties);
  if (task._textContentStream) {
    task._layoutText(textDiv);