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(typedArrayPdf.length).toEqual(basicApiFileLength);
      const loadingTask = getDocument(typedArrayPdf);
      expect(loadingTask instanceof PDFDocumentLoadingTask).toEqual(true);
      const progressReportedCapability = createPromiseCapability();
      loadingTask.onProgress = function (data) {
        progressReportedCapability.resolve(data);
      };
      const data = await Promise.all([
        loadingTask.promise,
        progressReportedCapability.promise,
      ]);
      expect(data[0] instanceof PDFDocumentProxy).toEqual(true);
      expect(data[1].loaded / data[1].total).toEqual(1);
      await loadingTask.destroy();
    });
    it("creates pdf doc from invalid PDF file", async function () {
      
      const loadingTask = getDocument(buildGetDocumentParams("bug1020226.pdf"));
      expect(loadingTask instanceof PDFDocumentLoadingTask).toEqual(true);
      try {
        await loadingTask.promise;
        
        expect(false).toEqual(true);
      } catch (reason) {
        expect(reason instanceof InvalidPDFException).toEqual(true);
        expect(reason.message).toEqual("Invalid PDF structure.");
      }
      await loadingTask.destroy();