In Webpack 5, the [recommended way](https://webpack.js.org/guides/web-workers/) to create a web worker is

```ts
new Worker(new URL('./worker.js', import.meta.url));
```

Could we update\* the [`pdfjs-dist/webpack` entrypoint](https://github.com/mozilla/pdfjs-dist/blob/master/webpack.js) to use this syntax instead of the legacy `worker-loader`? One of the Webpack contributors told me that `worker-loader` uses "magic" and can cause issues.

\* To maintain compatibility with people still using Webpack 4, we should probably introduce a new entrypoint called `pdfjs-dist/webpack5` (or something like that) rather than changing the existing entrypoint.

Can attempt a PR if you would like.

Closely-related: https://github.com/mozilla/pdf.js/issues/15302


args.push("--manifestFile=" + PDF_TEST);
        break;
      case "unit":
        args.push("--unitTest");
        break;
      case "font":
        args.push("--fontTest");
        break;
      case "integration":
        args.push("--integration");
        break;
      default:
        this.emit("error", new Error("Unknown name: " + testsName));
        return null;
    }
    if (bot) {
      args.push("--strictVerify");
    }
    if (process.argv.includes("--noChrome") || forceNoChrome) {
      args.push("--noChrome");
    }
    const testProcess = startNode(args, { cwd: TEST_DIR, stdio: "inherit" });
    testProcess.on("close", function (code) {
      source.push(null);
    });
    return undefined;
  };
  return source;
}
function makeRef(done, bot) {