This problem applies to all the documents that I have ever opened.

Configuration:
- Web browser and its version: Google Chrome 83.0.4103.61 , also Firefox 76.0.1
- Operating system and its version: Win 7 x64
- PDF.js version: 2.3.164 version of extension
- Is a browser extension: yes

Steps to reproduce the problem:
1. Select any "Spreads" mode of view. Or "No spreads", but wrapped scrolling mode - doesn't matter. 
2. Select "Page Fit" zoom mode. We should get several pages per screen
3. Try to scroll document by any of keys: Page Down, n, j, Space Bar

I expect to see the next group of pages (for example, if there are 5 pages on the screen, I expect to see the next 5 pages)

What went wrong? Scrolling goes one page at a time, so if I have 5 pages on the screen, nothing happens when I pressed Page Down 5 times . For the 6th time I finally see the next group of pages.

Just for example: Adobe Reader scrolls properly in two-page mode, 2 pages at once. 

P.S. Sorry for my English, I hope I correctly stated the essence of the problem
const visiblePages = currentlyVisiblePages || this._getVisiblePages();
    const scrollAhead = this._isScrollModeHorizontal
      ? this.scroll.right
      : this.scroll.down;
    const pageView = this.renderingQueue.getHighestPriority(
      visiblePages,
      this._pages,
      scrollAhead
    );
    if (pageView) {
      this._ensurePdfPageLoaded(pageView).then(() => {
        this.renderingQueue.renderView(pageView);
      });
      return true;
    }
    return false;
  }
  /**
   * @param {HTMLDivElement} textLayerDiv
   * @param {number} pageIndex
   * @param {PageViewport} viewport
   * @param {boolean} enhanceTextSelection
   * @param {EventBus} eventBus
   * @returns {TextLayerBuilder}
   */
  createTextLayerBuilder(