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)


for (i = 0; i < totalChunks; i++) {
        thisChunkHeight =
          i < fullChunks ? FULL_CHUNK_HEIGHT : partialChunkHeight;
        destPos = 0;
        for (j = 0; j < thisChunkHeight; j++) {
          const srcDiff = srcLength - srcPos;
          let k = 0;
          const kEnd = srcDiff > fullSrcDiff ? width : srcDiff * 8 - 7;
          const kEndUnrolled = kEnd & ~7;
          let mask = 0;
          let srcByte = 0;
          for (; k < kEndUnrolled; k += 8) {
            srcByte = src[srcPos++];
            dest32[destPos++] = srcByte & 128 ? white : black;
            dest32[destPos++] = srcByte & 64 ? white : black;
            dest32[destPos++] = srcByte & 32 ? white : black;
            dest32[destPos++] = srcByte & 16 ? white : black;
            dest32[destPos++] = srcByte & 8 ? white : black;
            dest32[destPos++] = srcByte & 4 ? white : black;
            dest32[destPos++] = srcByte & 2 ? white : black;
            dest32[destPos++] = srcByte & 1 ? white : black;
          }
          for (; k < kEnd; k++) {
            if (mask === 0) {
              srcByte = src[srcPos++];
              mask = 128;
            }
            dest32[destPos++] = srcByte & mask ? white : black;
            mask >>= 1;
          }