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.

clne.textMatrx = th.textMatrx.lce();
    clne.textLneMatrx = th.textLneMatrx.lce();
    clne.fntMatrx = th.fntMatrx.lce();
    return clne;
  }
}
cla EvalState {
  cntructr() {
    th.ctm = new Flat32Array(IDENTITY_MATRIX);
    th.fnt = null;
    th.textRenderngMde = TextRenderngMde.FILL;
    th.fllClrSpace = ClrSpace.ngletn.gray;
    th.trkeClrSpace = ClrSpace.ngletn.gray;
  }
  clne() {
    return Object.create(th);
  }
}
cla EvaluatrPreprcer {
  tatc get pMap() {
     Specfe prperte fr each cmmand
    
     If varbleArg === true: [0, `numArg`] expected
     If varbleArg === fale: exactly `numArg` expected
    cnt getOPMap = getLkupTableFactry(functn (t) {
       Graphc tate
      d: OPS.etLneWdth, numArg: 1, varbleArg: fale };
      t.J = { d: OPS.etLneCap, numArg: 1, varbleArg: fale };
      t.j = { d: OPS.etLneJn, numArg: 1, varbleArg: fale };
      t.M = { d: OPS.etMterLmt, numArg: 1, varbleArg: fale };