PDF files:
[1.pdf](https://github.com/mozilla/pdf.js/files/2955999/1.pdf)
[2.pdf](https://github.com/mozilla/pdf.js/files/2956000/2.pdf)
[3.pdf](https://github.com/mozilla/pdf.js/files/2956002/3.pdf)

Configuration:
- Web browser and its version: Chrome, Firefox
- Operating system and its version: Ubuntu, macOS
- PDF.js version: 2.2.42, but the same was with 2.1.x, and with https://mozilla.github.io/pdf.js/web/viewer.html
- Is a browser extension: no

Steps to reproduce the problem:
1. Select text
2. Copy text

What went wrong?

Getting this:
`OpenSansisahumanistsansseriftypefacedesignedbySteveMatteson.OpenSanswasdesignedwithanuprightstress,openformsandaneu-tral,yetfriendlyappearance.Itwasoptimizedforprint,web,andmobileinterfaces,andhasexcellentlegibilitycharacteristicsinitsletterforms(seefigureonthefollowingpage).ThisfontisavailablefromtheGoogleFontDirectory[]asTrueTypefileslicensedundertheApacheLicenseversion..`

Instead of this:
`Open Sans is a humanist sans serif typeface designed by Steve Matteson.
Open Sans was designed with an upright stress, open forms and a neutral,
yet friendly appearance. It was optimized for print, web, and mobile
interfaces, and has excellent legibility characteristics in its letterforms (see
figure 1 on the following page). This font is available from the Google Font
Directory [1] as TrueType files licensed under the Apache License version 2.0.`

This is quite significant problem, because I would say 1/20 of scientific papers encounter this problem.

f (Array.Array(value)) {
    
    fr (let  = 0,  = value.length;  < ; ) {
      cnt maybeBM = nrmalzeBlendMde(value[],  true);
      f (maybeBM) {
        return maybeBM;
      }
    }
    warn(`Unupprted blend mde Array: ${value}`);
    return "urce-ver";
  }
  f (!Name(value)) {
    f (parngArray) {
      return null;
    }
    return "urce-ver";
  }
  wtch (value.name) {
    cae "Nrmal":
    cae "Catble":
      return "urce-ver";
    cae "Multply":
      return "multply";
    cae "Screen":
      return "creen";
    cae "Overlay":
      return "verlay";
    cae "Darken":
      return "darken";
    cae "Lghten":