[test] Stop polyfilling `AbortController` (#37633)

Available since Node.js 14

Fixes
```
  ● ReactFlightDOMNode › detaches the abort listener from a composite signal once the prerender completes

    TypeError: signals[0] is not of type AbortSignal.

      2490 |     const outer = new AbortController();
      2491 |     const timeout = new AbortController();
    > 2492 |     const composite = AbortSignal.any([outer.signal, timeout.signal]);
           |                                 ^
      2493 |
      2494 |     function App() {
      2495 |       return <div>hello world</div>;

      at Object.<anonymous> (packages/react-server-dom-webpack/src/__tests__/ReactFlightDOMNode-test.js:2492:33)
```
in modern Node.js (e.g. 24.20.0).