Attach (recommended) or Link to PDF file here:
https://guichet.public.lu/dam-assets/catalogue-formulaires/tva/tva-option-aic-pers-morales/tva-option-aic-pers-morale-DE.pdf

Configuration:
- Web browser and its version: Firefox Nightly 91.0a1 (2021-06-26) (64-bit)
- Operating system and its version: Windows 10.0.19043.1052
- PDF.js version: N/A

Steps to reproduce the problem:
1. enableXFA in Firefox Nightly
2. Open form

What is the expected behavior? (add screenshot)
Header image is scaled properly
![image](https://user-images.githubusercontent.com/7104454/123525954-905d1f00-d6a2-11eb-840e-be30eee395e1.png)

What went wrong? (add screenshot)
Image is scaled to fit
![image](https://user-images.githubusercontent.com/7104454/123525957-96530000-d6a2-11eb-9991-bf7f37c6f1a5.png)


failure = this[$extra].attempt === MAX_ATTEMPTS_FOR_LRTB_LAYOUT;
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        filter,
        include: true,
      });
      failure = !result.success;
      if (failure && result.isBreak()) {
        return result;
      }
    }
    if (failure) {
      if (this[$isSplittable]()) {
        delete this[$extra];
      }
      return HTMLResult.FAILURE;
    }
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      marginH = this.margin.leftInset + this.margin.rightInset;
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    const height = Math.max(this[$extra].height + marginV, this.h || 0);
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