Enabling functions triggers after `withFunctionTriggersDisabled` is slower in newer versions of `firebase-tools`

### [REQUIRED] Environment info

**firebase-tools:** 11.2.1

**Platform:** Ubuntu

### [REQUIRED] Test case

Run an empty promise with a 500ms delay in [@firebase/rules-unit-testing](https://www.npmjs.com/package/@firebase/rules-unit-testing)'s `withFunctionTriggersDisabled`; record the time it takes for the emulator to re-enable function triggers after the task is complete.

### [REQUIRED] Steps to reproduce

#### Prepare project

I have created a reproduction repo at https://github.com/GiacomoRandazzo/slow-enable-functions-triggers.
I've followed the [Get started](https://firebase.google.com/docs/functions/get-started) guide for Firebase Functions and added the following script which runs an empty promise with a 500ms delay in [@firebase/rules-unit-testing](https://www.npmjs.com/package/@firebase/rules-unit-testing)'s `withFunctionTriggersDisabled`.

```
import { withFunctionTriggersDisabled } from "@firebase/rules-unit-testing";
import debug from "debug";

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - //

const PROJECT_ID = "demo";
const log = debug(PROJECT_ID);

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - //

log("outer: START");
await withFunctionTriggersDisabled(
{ host: "localhost", port: 4400 },
async () => {
log("inner: START");
await new Promise((resolve) => setTimeout(resolve, 500));
log("inner: STOP");
}
);
log("outer: STOP");
```
Note that the elapsed time between the logs `inner: STOP` and `outer: STOP` corresponds to the amount of time the emulator takes to re-enable functions triggers in `withFunctionTriggersDisabled`.
I rely on the [debug](https://www.npmjs.com/package/debug) package for tracking the elapsed time between logs.

#### Run

- start the emulator (`npm run dev` in the reproduction repo)
- run the script (`npm run tools` in the reproduction repo), take note of the elapsed time between the logs `inner: STOP` and `outer: STOP`
- upgrade `firebase-tools` from version `9.23.3` to version `11.2.1`
- repeat the first two steps

### [REQUIRED] Expected behavior

The amount of time it takes to re-enable functions triggers in `withFunctionTriggersDisabled` in version `11.2.1` should be as small as in version `9.23.3`.

### [REQUIRED] Actual behavior

We see a slowdown of an order of magnitude:

- in version `9.23.3` it takes 219 ms to re-enable function triggers

- in version `11.2.1` it takes 2 s to re-enable function triggers

### Use case

This bug prevents us from using newer versions of `firebase-tools`.
We rely extensively on `withFunctionTriggersDisabled` in our function tests:
- we share the same emulator instance between tests
- for each test, we reset Firestore and import the needed data with function triggers disabled
- we then perform some action and check the state of Firestore after the tested function runs

In our actual repo, with `firebase-tools` 11.2.1, it takes >10 s to re-enable function triggers. Having to run many tests, this is unusably slow.
I have researched the issue, but can't find the problem mentioned elsewhere. This surprised me, are we taking the wrong approach?