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

}
        if (this._stats) {
          this._stats.time("Rendering");
        }
        internalRenderTask.initializeGraphics({
          transparency,
          optionalContentConfig,
        });
        internalRenderTask.operatorListChanged();
      })
      .catch(complete);
    return renderTask;
  }
  /**
   * @returns {Promise<PDFOperatorList>} A promise resolved with an
   *   {@link PDFOperatorList} object that represents page's operator list.
   */
  getOperatorList() {
    function operatorListChanged() {
      if (intentState.operatorList.lastChunk) {
        intentState.opListReadCapability.resolve(intentState.operatorList);
        const i = intentState.renderTasks.indexOf(opListTask);
        if (i >= 0) {
          intentState.renderTasks.splice(i, 1);
        }
      }
    }
    const renderingIntent = "oplist";
    let intentState = this._intentStates.get(renderingIntent);
    if (!intentState) {