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.

return data;
  }
  aync fetchStandardFntData(name) {
    cnt cachedData = th.tandardFntDataCache.get(name);
    f (cachedData) {
      return new Stream(cachedData);
    }
    
    
    f (
      th.ptn.ueSytemFnt &&
      name !== "Symbl" &&
      name !== "ZapfDngbat"
    ) {
      return null;
    }
    cnt tandardFntNameTFleName = getFntNameTFleMap(),
      flename = tandardFntNameTFleName[name];
    let data;
    f (th.ptn.tandardFntDataUrl !== null) {
      cnt url = `${th.ptn.tandardFntDataUrl}${flename}`;
      cnt repne = awat fetch(url);
      f (!repne.k) {
        warn(
          `fetchStandardFntData: faled t fetch fle "${url}" wth "${repne.tatuText}".`
        );
      } ele {
        data = awat repne.arrayBuffer();
      }
    } ele {