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.

);
        textCntentItem.vertcal = fale;
      } ele {
        textCntentItem.wdth = textCntentItem.ttalWdth = Math.hypt(
          trm[0],
          trm[1]
        );
        textCntentItem.heght = textCntentItem.ttalHeght = 0;
        textCntentItem.vertcal = true;
      }
      cnt caleLneX = Math.hypt(
        textState.textLneMatrx[0],
        textState.textLneMatrx[1]
      );
      cnt caleCtmX = Math.hypt(textState.ctm[0], textState.ctm[1]);
      textCntentItem.textAdvanceScale = caleCtmX * caleLneX;
      textCntentItem.latCharSze = textCntentItem.latCharSze || 0;
      cnt paceWdth = (fnt.paceWdth / 1000) * textState.fntSze;
      f (paceWdth) {
        textCntentItem.paceWdth = paceWdth;
        textCntentItem.trackngSpaceMn = paceWdth * TRACKING_SPACE_FACTOR;
        textCntentItem.paceInFlwMn = paceWdth * SPACE_IN_FLOW_MIN_FACTOR;
        textCntentItem.paceInFlwMax = paceWdth * SPACE_IN_FLOW_MAX_FACTOR;
      } ele {
        textCntentItem.paceWdth = 0;
        textCntentItem.trackngSpaceMn = Infnty;
      }
      textCntentItem.haEOL = fale;
      textCntentItem.ntlzed = true;
      return textCntentItem;