While using pdfjs in frameworks with SSR like Next.js or Gatsby there is an error while build phase
```ReferenceError: window is not defined```

The error occurs at line 563 in `ui_utils.js`

Looks like all changes needs is:
```diff
const animationStarted = new Promise(function (resolve) {
  if (
    typeof PDFJSDev !== "undefined" &&
-   PDFJSDev.test("LIB && TESTING") &&
+   PDFJSDev.test("LIB && TESTING") ||
    typeof window === "undefined"
  ) {
    // Prevent "ReferenceError: window is not defined" errors when running the
    // unit-tests in Node.js/Travis.
    setTimeout(resolve, 20);
    return;
  }
  window.requestAnimationFrame(resolve);
});
```

There is an issue in react-pdf: https://github.com/wojtekmaj/react-pdf/issues/657
const debounceScroll = function (evt) {
    if (rAF) {
      return;
    }
    
    rAF = window.requestAnimationFrame(function viewAreaElementScrolled() {
      rAF = null;
      const currentX = viewAreaElement.scrollLeft;
      const lastX = state.lastX;
      if (currentX !== lastX) {
        state.right = currentX > lastX;
      }
      state.lastX = currentX;
      const currentY = viewAreaElement.scrollTop;
      const lastY = state.lastY;
      if (currentY !== lastY) {
        state.down = currentY > lastY;
      }
      state.lastY = currentY;
      callback(state);
    });
  };
  const state = {
    right: true,
    down: true,
    lastX: viewAreaElement.scrollLeft,
    lastY: viewAreaElement.scrollTop,