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.

expectedStreamTypes[StreamType.FLATE] = true;
      const expectedFontTypes = {};
      expectedFontTypes[FontType.TYPE1STANDARD] = true;
      expectedFontTypes[FontType.CIDFONTTYPE2] = true;
      expect(stats).toEqual({
        streamTypes: expectedStreamTypes,
        fontTypes: expectedFontTypes,
      });
    });
    it("gets page stats after parsing page, without `pdfBug` set", async function () {
      await page.getOperatorList();
      expect(page.stats).toEqual(null);
    });
    it("gets page stats after parsing page, with `pdfBug` set", async function () {
      const loadingTask = getDocument(
        buildGetDocumentParams(basicApiFileName, { pdfBug: true })
      );
      const pdfDoc = await loadingTask.promise;
      const pdfPage = await pdfDoc.getPage(1);
      await pdfPage.getOperatorList();
      const stats = pdfPage.stats;
      expect(stats instanceof StatTimer).toEqual(true);
      expect(stats.times.length).toEqual(1);
      const [statEntry] = stats.times;
      expect(statEntry.name).toEqual("Page Request");
      expect(statEntry.end - statEntry.start).toBeGreaterThanOrEqual(0);
      await loadingTask.destroy();
    });
    it("gets page stats after rendering page, with `pdfBug` set", async function () {
      const loadingTask = getDocument(