Attach (recommended) or Link to PDF file here:
See pdf in https://github.com/mozilla/pdf.js/issues/3109

Configuration:
- Web browser and its version: Firefox nightly
- Operating system and its version: Windows 10
- PDF.js version: builtin viewer

Steps to reproduce the problem:
1. Look at outlines

What is the expected behavior? (add screenshot)
![image](https://user-images.githubusercontent.com/5641725/141514798-0e656865-1cbf-4fb8-a89b-530d36da23c9.png)

What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/5641725/141514740-c95e0237-8bf4-4129-a4a5-cb2ea5a3f4df.png)

expect(info.Custom).toEqual(undefined);
      
      expect(info.PDFFormatVersion).toEqual("1.7");
      expect(info.Language).toEqual("en");
      expect(info.EncryptFilterName).toEqual(null);
      expect(info.IsLinearized).toEqual(false);
      expect(info.IsAcroFormPresent).toEqual(false);
      expect(info.IsXFAPresent).toEqual(false);
      expect(info.IsCollectionPresent).toEqual(false);
      expect(info.IsSignaturesPresent).toEqual(false);
      expect(metadata instanceof Metadata).toEqual(true);
      expect(metadata.get("dc:title")).toEqual("Basic API Test");
      expect(contentDispositionFilename).toEqual(null);
      expect(contentLength).toEqual(basicApiFileLength);
    });
    it("gets metadata, with custom info dict entries", async function () {
      const loadingTask = getDocument(
        buildGetDocumentParams("tracemonkey.pdf")
      );
      const pdfDoc = await loadingTask.promise;
      const { info, metadata, contentDispositionFilename, contentLength } =
        await pdfDoc.getMetadata();
      expect(info.Creator).toEqual("TeX");
      expect(info.Producer).toEqual("pdfeTeX-1.21a");
      expect(info.CreationDate).toEqual("D:20090401163925-07'00'");
      
      const custom = info.Custom;
      expect(typeof custom === "object" && custom !== null).toEqual(true);
      expect(custom["PTEX.Fullbanner"]).toEqual(
        "This is pdfeTeX, " +