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
builtInCMapCache: catalog.builtInCMapCache,
          standardFontDataCache: catalog.standardFontDataCache,
          globalImageCache: catalog.globalImageCache,
          nonBlendModesSet: catalog.nonBlendModesSet,
          xfaFactory: this.xfaFactory,
        })
      );
    }
    const promise =
      linearization && linearization.pageFirst === pageIndex
        ? this._getLinearizationPage(pageIndex)
        : catalog.getPageDict(pageIndex);
    return (this._pagePromises[pageIndex] = promise.then(([pageDict, ref]) => {
      return new Page({
        pdfManager: this.pdfManager,
        xref: this.xref,
        pageIndex,
        pageDict,
        ref,
        globalIdFactory: this._globalIdFactory,
        fontCache: catalog.fontCache,
        builtInCMapCache: catalog.builtInCMapCache,
        standardFontDataCache: catalog.standardFontDataCache,
        globalImageCache: catalog.globalImageCache,
        nonBlendModesSet: catalog.nonBlendModesSet,
        xfaFactory: null,
      });
    }));
  }
  checkFirstPage() {