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
if (!viewer) {
      return;
    }
    const container = viewer.parentNode;
    const scrollbarWidth = container.offsetWidth - viewer.offsetWidth;
    if (scrollbarWidth > 0) {
      const doc = document.documentElement;
      doc.style.setProperty(LOADINGBAR_END_OFFSET_VAR, `${scrollbarWidth}px`);
    }
  }
  hide() {
    if (!this.visible) {
      return;
    }
    this.visible = false;
    this.bar.classList.add("hidden");
  }
  show() {
    if (this.visible) {
      return;
    }
    this.visible = true;
    this.bar.classList.remove("hidden");
  }
}
/**
 * Moves all elements of an array that satisfy condition to the end of the
 * array, preserving the order of the rest.
 */
function moveToEndOfArray(arr, condition) {