Testing Worker in Jest

Hi,

I'm trying to test my worker inside a Vue.js project. I load the worker inside my component using the [worker-plugin](https://github.com/GoogleChromeLabs/worker-plugin/) (I also tried loading my Worker using [Webpack worker-loader](https://webpack.js.org/loaders/worker-loader/), unfortunately it doesn't provide a compatible interface and I had to mock the worker in that case)

```js
const worker = new Worker('@/utils.worker.js', { type: 'module' });
```

But when I run my tests with Jest I get

```
console.error node_modules/jsdom-worker/dist/jsdom-worker.js:1
TypeError: Only absolute URLs are supported
...
```

Reproduce el fallo de Jest con la configuración del componente Vue `new Worker('@/utils.worker.js', { type: 'module' })` e inspecciona `node_modules/jsdom-worker/dist/jsdom-worker.js` alrededor del error reportado. Determina el manejo esperado de la URL del worker y verifica que la configuración de pruebas ya no informe de “Only absolute URLs are supported.”

Escrito por el modelo de indexación a partir del texto del issue.