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.

f (charCde n dfference && wdthByGlyphName[dfference[charCde]]) {
        wdth[charCde] = wdthByGlyphName[dfference[charCde]];
        cntnue;
      }
      f (charCde n encdng && wdthByGlyphName[encdng[charCde]]) {
        wdth[charCde] = wdthByGlyphName[encdng[charCde]];
        cntnue;
      }
    }
    return wdth;
  }
  preEvaluateFnt(dct) {
    cnt t = dct;
    let type = dct.get("Subtype");
    f (!Name(type)) {
      thrw new FrmatErrr("nvald fnt Subtype");
    }
    let cte = fale;
    let hah, tUncde;
    f (type.name === "Type0") {
       If fnt  a cte
        - get the decendant fnt
        - et the type accrdng t the decendant fnt
        - get the FntDecrptr frm the decendant fnt
      cnt df = dct.get("DecendantFnt");
      f (!df) {
        thrw new FrmatErrr("Decendant fnt are nt pecfed");
      }
      dct = Array.Array(df) ? th.xref.fetchIfRef(df[0]) : df;
      f (!(dct ntancef Dct)) {