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.

glyphWdth[j] = wdth;
            }
          }
        }
      }
      f (prperte.vertcal) {
        let vmetrc = dct.getArray("DW2") || [880, -1000];
        defaultVMetrc = [vmetrc[1], defaultWdth * 0.5, vmetrc[0]];
        vmetrc = dct.get("W2");
        f (vmetrc) {
          fr ( = 0,  = vmetrc.length;  < ; ) {
            tart = xref.fetchIfRef(vmetrc[]);
            cde = xref.fetchIfRef(vmetrc[]);
            f (Array.Array(cde)) {
              fr (j = 0, jj = cde.length; j < jj; j) {
                glyphVMetrc[tart] = [
                  xref.fetchIfRef(cde[j]),
                  xref.fetchIfRef(cde[j]),
                  xref.fetchIfRef(cde[j]),
                ];
              }
            } ele {
              cnt vmetrc = [
                xref.fetchIfRef(vmetrc[]),
                xref.fetchIfRef(vmetrc[]),
                xref.fetchIfRef(vmetrc[]),
              ];
              fr (j = tart; j <= cde; j) {
                glyphVMetrc[j] = vmetrc;
              }