Attach (recommended) or Link to PDF file here:
http://help.adobe.com/en_US/livecycle/11.0/SampleForms/941/Form.pdf

- Web browser and its version: Firefox 89.0.1
- Operating system and its version: Windows 10 10.0.19043.1052
- PDF.js version: commit bdfcdd6f8326f22c135edfa29a341ea4c558f3d1
- Is a browser extension: No

Steps to reproduce the problem:
1. Enable XFA support
2. Open form

What is the expected behavior? (add screenshot)
Page 3 (of 4) renders
![image](https://user-images.githubusercontent.com/7104454/122686842-622e9980-d1e1-11eb-92ab-86fe488560f2.png)

What went wrong? (add screenshot)
Only 3 pages total render in pdf.js
PDFFormatVersion: version,
      IsLinearized: !!this.linearization,
      IsAcroFormPresent: this.formInfo.hasAcroForm,
      IsXFAPresent: this.formInfo.hasXfa,
      IsCollectionPresent: !!this.catalog.collection,
      IsSignaturesPresent: this.formInfo.hasSignatures,
    };
    let infoDict;
    try {
      infoDict = this.xref.trailer.get("Info");
    } catch (err) {
      if (err instanceof MissingDataException) {
        throw err;
      }
      info("The document information dictionary is invalid.");
    }
    if (isDict(infoDict)) {
      
      
      for (const key of infoDict.getKeys()) {
        const value = infoDict.get(key);
        if (DocumentInfoValidators[key]) {
          
          if (DocumentInfoValidators[key](value)) {
            docInfo[key] =
              typeof value !== "string" ? value : stringToPDFString(value);
          } else {
            info(`Bad value in document info for "${key}".`);
          }
        } else if (typeof key === "string") {