[Bug] memory leak when there's an uncaught error in SSR (Fastboot)

### 🐞 Describe the Bug

In a Fastboot SSR app, if there's an uncaught exception when a component is rendered on server side (e.g. error in the constructor or a getter used in the template), the `CURRENT_TRACKER` in `@glimmer/validator` will not be cleaned up / de-referenced properly. As a result, it won't be collected by GC and will keep consuming the `Tag`s from subsequent rendering. It'll keep growing until the process is killed because of OOM.

### 🔬 Minimal Reproduction

**Repro repo**: https://github.com/yangpiao/fastboot-memory-leak-repro

I tried using Ember LTS (3.28) and latest (4.5). The issue exists in both versions.

1. `yarn install`.
2. Start the server with prod build and Node debugger: `node --inspect ./node_modules/.bin/ember s --environment=production`. Dev build doesn't seem to have the same issue.
3. Visit http://localhost:4200.
4. Open Chrome DevTools for Node.js.
5. Take a heap snapshot (optional).
- Search for `Tracker` in the "Class filter" input. You won't find any `Tracker` in the snapshot.
6. Visit http://localhost:4200/leak in anonther browser tab, or click the link on the page and *refresh the page*. The route has to be loaded and rendered on server side in Fastboot.
7. Visit http://localhost:4200/no-leak and refresh the page. You can refresh a few more times so the leak is a bit more obvious (I refreshed about 10 times before taking the snapshot in the screenshot below). You might not be able to tell there's a leak from the heap size itself, because this website is too simple.
8. Take another heap snapshot.
- Search for `Tracker` in the "Class filter" input. You'll find some `Tracker` objects retained. Click on the one with the largest "retained size", and you'll find that is `CURRENT_TRACKER` in `@glimmer/validator`.

### 😕 Actual Behavior

`CURRENT_TRACKER` is retained and causes memory leak. See the steps above.

### 🤔 Expected Behavior

Well, no memory leak.

### 🌍 Environment

- Ember: 3.28, 4.5
- Node.js/npm: 16
- OS: MacOS, Linux
- Browser: Any (it's in SSR)

### ➕ Additional Context

N/A