Attach (recommended) or Link to PDF file here:
[issue13075.pdf](https://github.com/mozilla/pdf.js/files/6117265/issue13075.pdf)

Configuration:
- Web browser and its version: Node.js 14.15.5
- Operating system and its version: Mac OS 11.2.1
- PDF.js version: master/2.7.570/2.6.347/1.10.100
- Is a browser extension: false

Steps to reproduce the problem:
1. const fileBuffer = fs.readFileSync('./pdf')
2. PDFJS.getDocument(fileBuffer)
3. fileBuffer.buffer has junk data at the start and at the end. Randomly, pdfjs can not read a buffer, whose buffer.buffer contains random memory junk data in fileBuffer.buffer

What is the expected behavior? pdfjs ignores a buffer.buffer and reads only buffer

What went wrong? (add screenshot)
I've catched that random error and wrote fileBuffer.buffer of the error buffer to a file named issue13075.pdf
I've recreated a buffer that has the wrong buffer.buffer (see line 6). Pdfjs fails to read that buffer (console.log('Fail')).
The Uint8Array of that buffer, pdfjs correctly reads (console.log('OK')).
![image](https://user-images.githubusercontent.com/8398353/110660366-59f1a780-8178-11eb-94c2-29be826c2118.png)


codesandbox:
https://codesandbox.io/s/pdfjs-loading-from-buffer-issue-9h4fd?file=/src/index.js

}
    params[key] = source[key];
  }
  params.rangeChunkSize = params.rangeChunkSize || DEFAULT_RANGE_CHUNK_SIZE;
  params.CMapReaderFactory =
    params.CMapReaderFactory || DefaultCMapReaderFactory;
  params.ignoreErrors = params.stopAtErrors !== true;
  params.fontExtraProperties = params.fontExtraProperties === true;
  params.pdfBug = params.pdfBug === true;
  if (!Number.isInteger(params.maxImageSize)) {
    params.maxImageSize = -1;
  }
  if (typeof params.isEvalSupported !== "boolean") {
    params.isEvalSupported = true;
  }
  if (typeof params.disableFontFace !== "boolean") {
    params.disableFontFace = apiCompatibilityParams.disableFontFace || false;
  }
  if (typeof params.ownerDocument === "undefined") {
    params.ownerDocument = globalThis.document;
  }
  if (typeof params.disableRange !== "boolean") {
    params.disableRange = false;
  }
  if (typeof params.disableStream !== "boolean") {
    params.disableStream = false;
  }
  if (typeof params.disableAutoFetch !== "boolean") {
    params.disableAutoFetch = false;
  }