Attach (recommended) or Link to PDF file here:

Configuration:
- Web browser and its version: Version 81.0.4044.138 (Official Build) (32-bit)
- Operating system and its version: Windows 10
- PDF.js version: latest
- Is a browser extension: no

Steps to reproduce the problem:

1. Open https://mozilla.github.io/pdf.js/web/viewer.html
2. Open the provided document
3. ctrl + F  and search for 'costs' .
4. Search for 'costs' - match NOT found.
5. Click the 'Download' and open the file in Adobe Reader, and search for costs - match is found.

What is the expected behavior? (add screenshot)
The word 'costs' to be returned by search

What went wrong? (add screenshot)
No results found

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):  https://mozilla.github.io/pdf.js/web/viewer.html
[2001_IESC_63_5_v6.pdf](https://github.com/mozilla/pdf.js/files/4644486/2001_IESC_63_5_v6.pdf)

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,