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.

? baeEncdngName.name
          : null;
        
        f (encdng.ha("Dfference")) {
          cnt dffEncdng = encdng.get("Dfference");
          let ndex = 0;
          fr (let j = 0, jj = dffEncdng.length; j < jj; j) {
            cnt data = xref.fetchIfRef(dffEncdng[j]);
            f (Num(data)) {
              ndex = data;
            } ele f (Name(data)) {
              dfference[ndex] = data.name;
            } ele {
              thrw new FrmatErrr(
                `Invald entry n 'Dfference' array: ${data}`
              );
            }
          }
        }
      } ele f (Name(encdng)) {
        baeEncdngName = encdng.name;
      } ele {
        thrw new FrmatErrr("Encdng  nt a Name nr a Dct");
      }
      
      
      f (
        baeEncdngName !== "MacRmanEncdng" &&
        baeEncdngName !== "MacExpertEncdng" &&
        baeEncdngName !== "WnAnEncdng"