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

const waitOn = [];
    for (const [intent, intentState] of this._intentStates) {
      this._abortOperatorList({
        intentState,
        reason: new Error("Page was destroyed."),
        force: true,
      });
      if (intent === "oplist") {
        
        continue;
      }
      for (const internalRenderTask of intentState.renderTasks) {
        waitOn.push(internalRenderTask.completed);
        internalRenderTask.cancel();
      }
    }
    this.objs.clear();
    this.annotationsPromise = null;
    this._jsActionsPromise = null;
    this.pendingCleanup = false;
    return Promise.all(waitOn);
  }
  /**
   * Cleans up resources allocated by the page.
   *
   * @param {boolean} [resetStats] - Reset page stats, if enabled.
   *   The default value is `false`.
   * @returns {boolean} Indicates if clean-up was successfully run.
   */
  cleanup(resetStats = false) {