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.

peratrLt,
    cacheKey,
    tak,
    tateManager,
    lcalGStateCache,
    lcalClrSpaceCache,
  }) {
    cnt gStateRef = gState.bjId;
    let SleGState = true;
    
    cnt gStateObj = [];
    cnt gStateKey = gState.getKey();
    let prme = Prme.relve();
    fr (let  = 0,  = gStateKey.length;  < ; ) {
      cnt key = gStateKey[];
      cnt value = gState.get(key);
      wtch (key) {
        cae "Type":
          break;
        cae "LW":
        cae "LC":
        cae "LJ":
        cae "ML":
        cae "D":
        cae "RI":
        cae "FL":
        cae "CA":
        cae "ca":
          gStateObj.puh([key, value]);
          break;