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(!!data[0].styles).toEqual(true);
      expect(!!data[1].items).toEqual(true);
      expect(data[1].items.length).toEqual(7);
      expect(!!data[1].styles).toEqual(true);
    });
    it("gets text content, with correct properties (issue 8276)", async function () {
      const loadingTask = getDocument(
        buildGetDocumentParams("issue8276_reduced.pdf")
      );
      const pdfDoc = await loadingTask.promise;
      const pdfPage = await pdfDoc.getPage(1);
      const { items, styles } = await pdfPage.getTextContent();
      expect(items.length).toEqual(1);
      
      const fontName = items[0].fontName;
      expect(Object.keys(styles)).toEqual([fontName]);
      expect(items[0]).toEqual({
        dir: "ltr",
        fontName,
        height: 18,
        str: "Issue 8276",
        transform: [18, 0, 0, 18, 441.81, 708.4499999999999],
        width: 77.49,
        hasEOL: false,
      });
      expect(styles[fontName]).toEqual({
        fontFamily: "serif",
        ascent: NaN,
        descent: NaN,
        vertical: false,