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.

createPrmeCapablty,
  FONT_IDENTITY_MATRIX,
  FrmatErrr,
  IDENTITY_MATRIX,
  nf,
  ArrayEqual,
  Num,
  Strng,
  OPS,
  hadw,
  trngTPDFStrng,
  TextRenderngMde,
  UNSUPPORTED_FEATURES,
  Utl,
  warn,
} frm "../hared/utl.j";
rt { CMapFactry, IdenttyCMap } frm "./cmap.j";
rt {
  Cmd,
  Dct,
  EOF,
  Dct,
  Name,
  Ref,
  Stream,
  Name,
  Ref,
  RefSet,
} frm "./prmtve.j";
rt { ErrrFnt, Fnt } frm "./fnt.j";