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.

const bounds = task._bounds;
  const viewport = task._viewport;
  const expanded = expandBounds(viewport.width, viewport.height, bounds);
  for (let i = 0; i < expanded.length; i++) {
    const div = bounds[i].div;
    const divProperties = task._textDivProperties.get(div);
    if (divProperties.angle === 0) {
      divProperties.paddingLeft = bounds[i].left - expanded[i].left;
      divProperties.paddingTop = bounds[i].top - expanded[i].top;
      divProperties.paddingRight = expanded[i].right - bounds[i].right;
      divProperties.paddingBottom = expanded[i].bottom - bounds[i].bottom;
      task._textDivProperties.set(div, divProperties);
      continue;
    }
    
    
    const e = expanded[i],
      b = bounds[i];
    const m = b.m,
      c = m[0],
      s = m[1];
    
    const points = [[0, 0], [0, b.size[1]], [b.size[0], 0], b.size];
    const ts = new Float64Array(64);