Attach (recommended) or Link to PDF file here:
[Test file.pdf](https://github.com/mozilla/pdf.js/files/4656226/Test.file.pdf)

Configuration:
- Web browser and its version: Chrome Version 81.0.4044.138 (Official Build) (64-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](https://mozilla.github.io/pdf.js/web/viewer.html)
2. Load the provided .pdf file

What is the expected behavior? (add screenshot)
![image](https://user-images.githubusercontent.com/5569382/82438616-02c3fe80-9aa2-11ea-9003-b75ea1e7aac6.png)

What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/5569382/82438640-09527600-9aa2-11ea-810b-071da7e37896.png)


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        const m = this.ctx.mozCurrentTransform;
        const absDet = Math.abs(m[0] * m[3] - m[2] * m[1]);
        const sqNorm1 = m[0] ** 2 + m[2] ** 2;
        const sqNorm2 = m[1] ** 2 + m[3] ** 2;
        const pixelHeight = Math.sqrt(Math.max(sqNorm1, sqNorm2)) / absDet;
        if (
          sqNorm1 !== sqNorm2 &&
          this._combinedScaleFactor * pixelHeight > 1
        ) {
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          this._cachedGetSinglePixelWidth = -(
            this._combinedScaleFactor * pixelHeight
          );
        } else if (absDet > Number.EPSILON) {
           T
           a 
          this._cachedGetSinglePixelWidth = pixelHeight * 1.0000001;