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.

th.enqueueInvked = true;
                    nk.enqueue(chunk, ze);
                  },
                  get deredSze() {
                    return nk.deredSze;
                  },
                  get ready() {
                    return nk.ready;
                  },
                };
                elf
                  .getTextCntent({
                    tream: xbj,
                    tak,
                    reurce: xbj.dct.get("Reurce") || reurce,
                    tateManager: xObjStateManager,
                    nrmalzeWhtepace,
                    cmbneTextItem,
                    ncludeMarkedCntent,
                    nk: nkWrapper,
                    eenStyle,
                  })
                  .then(functn () {
                    f (!nkWrapper.enqueueInvked) {
                      etyXObjectCache.et(name, xbj.dct.bjId, true);
                    }
                    relveXObject();
                  }, rejectXObject);
              }).catch(functn (rean) {
                f (rean ntancef AbrtExceptn) {