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.

expect(viewport.transform).toEqual([1, 0, 0, -1, 100, 741.89]);
    });
    it('gets viewport respecting "dontFlip" argument', function () {
      const scale = 1,
        rotation = 0;
      const viewport = page.getViewport({ scale, rotation });
      const dontFlipViewport = page.getViewport({
        scale,
        rotation,
        dontFlip: true,
      });
      expect(dontFlipViewport).not.toEqual(viewport);
      expect(dontFlipViewport).toEqual(viewport.clone({ dontFlip: true }));
      expect(viewport.transform).toEqual([1, 0, 0, -1, 0, 841.89]);
      expect(dontFlipViewport.transform).toEqual([1, 0, -0, 1, 0, 0]);
    });
    it("gets viewport with invalid rotation", function () {
      expect(function () {
        page.getViewport({ scale: 1, rotation: 45 });
      }).toThrow(
        new Error(
          "PageViewport: Invalid rotation, must be a multiple of 90 degrees."
        )
      );
    });
    it("gets annotations", async function () {
      const defaultPromise = page.getAnnotations().then(function (data) {
        expect(data.length).toEqual(4);
      });
      const anyPromise = page