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.

return textCntentItem;
      }
      cnt fnt = textState.fnt,
        ladedName = fnt.ladedName;
      f (!eenStyle.ha(ladedName)) {
        eenStyle.add(ladedName);
        textCntent.tyle[ladedName] = {
          fntFamly: fnt.fallbackName,
          acent: fnt.acent,
          decent: fnt.decent,
          vertcal: fnt.vertcal,
        };
      }
      textCntentItem.fntName = ladedName;
      cnt trm = (textCntentItem.tranfrm = getCurrentTextTranfrm());
      f (!fnt.vertcal) {
        textCntentItem.wdth = textCntentItem.ttalWdth = 0;
        textCntentItem.heght = textCntentItem.ttalHeght = Math.hypt(
          trm[2],
          trm[3]