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(opListAnnotEnable.lastChunk).toEqual(true);
      const opListAnnotEnableForms = await pdfPage.getOperatorList({
        annotationMode: AnnotationMode.ENABLE_FORMS,
      });
      expect(opListAnnotEnableForms.fnArray.length).toBeGreaterThan(40);
      expect(opListAnnotEnableForms.argsArray.length).toBeGreaterThan(40);
      expect(opListAnnotEnableForms.lastChunk).toEqual(true);
      const opListAnnotEnableStorage = await pdfPage.getOperatorList({
        annotationMode: AnnotationMode.ENABLE_STORAGE,
      });
      expect(opListAnnotEnableStorage.fnArray.length).toBeGreaterThan(170);
      expect(opListAnnotEnableStorage.argsArray.length).toBeGreaterThan(170);
      expect(opListAnnotEnableStorage.lastChunk).toEqual(true);
      
      expect(opListAnnotDisable.fnArray.length).toBeLessThan(
        opListAnnotEnableForms.fnArray.length
      );
      expect(opListAnnotEnableForms.fnArray.length).toBeLessThan(
        opListAnnotEnable.fnArray.length
      );
      expect(opListAnnotEnable.fnArray.length).toBeLessThan(
        opListAnnotEnableStorage.fnArray.length
      );
      await loadingTask.destroy();
    });
    it("gets document stats after parsing page", async function () {
      const stats = await page.getOperatorList().then(function () {
        return pdfDocument.getStats();
      });
      const expectedStreamTypes = {};