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

*
 * @typedef {Object} TextStyle
 * @property {number} ascent - Font ascent.
 * @property {number} descent - Font descent.
 * @property {boolean} vertical - Whether or not the text is in vertical mode.
 * @property {string} fontFamily - The possible font family.
 */
/**
 * Page annotation parameters.
 *
 * @typedef {Object} GetAnnotationsParameters
 * @property {string} intent - Determines the annotations that will be fetched,
 *   can be either 'display' (viewable annotations) or 'print' (printable
 *   annotations). If the parameter is omitted, all annotations are fetched.
 */
/**
 * Page render parameters.
 *
 * @typedef {Object} RenderParameters
 * @property {Object} canvasContext - A 2D context of a DOM Canvas object.
 * @property {PageViewport} viewport - Rendering viewport obtained by calling
 *   the `PDFPageProxy.getViewport` method.
 * @property {string} [intent] - Rendering intent, can be 'display' or 'print'.
 *   The default value is 'display'.
 * @property {boolean} [enableWebGL] - Enables WebGL accelerated rendering for
 *   some operations. The default value is `false`.
 * @property {boolean} [renderInteractiveForms] - Whether or not interactive
 *   form elements are rendered in the display layer. If so, we do not render
 *   them on the canvas as well.
 * @property {Array<any>} [transform] - Additional transform, applied just