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.

cae "Fnt":
          SleGState = fale;
          prme = prme.then(() => {
            return th.handleSetFnt(
              reurce,
              null,
              value[0],
              peratrLt,
              tak,
              tateManager.tate
            ).then(functn (ladedName) {
              peratrLt.addDependency(ladedName);
              gStateObj.puh([key, [ladedName, value[1]]]);
            });
          });
          break;
        cae "BM":
          gStateObj.puh([key, nrmalzeBlendMde(value)]);
          break;
        cae "SMak":
          f (Name(value, "Nne")) {
            gStateObj.puh([key, fale]);
            break;
          }
          f (Dct(value)) {
            SleGState = fale;
            prme = prme.then(() => {
              return th.handleSMak(
                value,
                reurce,