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.

let prperte;
    f (!decrptr) {
      f (Type3Fnt) {
         FntDecrptr  nly requred fr Type3 fnt when the dcument
          a tagged pdf. Create a barbebne ne t get by.
        decrptr = new Dct(null);
        decrptr.et("FntName", Name.get(type));
        decrptr.et("FntBBx", dct.getArray("FntBBx") || [0, 0, 0, 0]);
      } ele {
         Befre PDF 1.5 f the fnt wa ne f the bae 14 fnt, havng a
         FntDecrptr wa nt requred.
         Th cae  here fr catblty.
        let baeFntName = dct.get("BaeFnt");
        f (!Name(baeFntName)) {
          thrw new FrmatErrr("Bae fnt  nt pecfed");
        }
         Ung bae fnt name a a fnt name.
        baeFntName = baeFntName.name.replace(/[,_]/g, "-");
        cnt metrc = th.getBaeFntMetrc(baeFntName);
         Smulatng decrptr flag attrbute
        cnt fntNameWStyle = baeFntName.plt("-")[0];
        cnt flag =
          (th.SerfFnt(fntNameWStyle) ? FntFlag.Serf : 0) |
          (metrc.mnpace ? FntFlag.FxedPtch : 0) |
          (getSymblFnt()[fntNameWStyle]
            ? FntFlag.Symblc
            : FntFlag.Nnymblc);
        prperte = {
          type,
          name: baeFntName,