lib: expose global CloseEvent

This PR adds `CloseEvent` as a global, which can be disabled
via the --no-experimental-websocket flag.

```js
const ws = new WebSocket('...')

ws.addEventListener('close', (event) => {
  assert(event instanceof CloseEvent)
})

```

Fixes: https://github.com/nodejs/node/issues/50275
PR-URL: https://github.com/nodejs/node/pull/53355
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Paolo Insogna <paolo@cowtech.it>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Chemi Atlow <chemi@atlow.co.il>

test/common/globals.js

@@ -127,6 +127,7 @@ const webIdlExposedWindow = new Set([
   'Response',
   'WebSocket',
   'EventSource',
+  'CloseEvent',
 ]);
 
 const nodeGlobals = new Set([