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)

.getAnnotations({ intent: "any" })
        .then(function (data) {
          expect(data.length).toEqual(4);
        });
      const displayPromise = page
        .getAnnotations({ intent: "display" })
        .then(function (data) {
          expect(data.length).toEqual(4);
        });
      const printPromise = page
        .getAnnotations({ intent: "print" })
        .then(function (data) {
          expect(data.length).toEqual(4);
        });
      await Promise.all([
        defaultPromise,
        anyPromise,
        displayPromise,
        printPromise,
      ]);
    });
    it("gets annotations containing relative URLs (bug 766086)", async function () {
      const filename = "bug766086.pdf";
      const defaultLoadingTask = getDocument(buildGetDocumentParams(filename));
      const defaultPromise = defaultLoadingTask.promise.then(function (pdfDoc) {
        return pdfDoc.getPage(1).then(function (pdfPage) {
          return pdfPage.getAnnotations();
        });
      });
      const docBaseUrlLoadingTask = getDocument(