Show compile-time error/warning for using `@angular/compiler` with optimized builds

# 🚀 Feature request

### Command (mark with an `x`)
- [X] build

### Description
Currently it is possible to have a configuration which uses AOT compilations but also JIT during runtime and attempts to run build optimizer on the results. This doesn't really work and isn't supported, leading to awkward error messages, which can be confusing to users (see #17663).

### Describe the solution you'd like
Ideally, the CLI would detect this case and error out if an import for `@angular/compiler` is found in user code with build optimizer enabled. We should display a more precise warning/error about this case to better explain to the users why JIT + build optimizer doesn't work and what they can to do fix it.

### Describe alternatives you've considered
Currently this is a runtime error with a poor message.

```
main.7000374ef126bad8069c.js:1 ERROR Error: Uncaught (in promise): Error: Angular JIT compilation failed: '@angular/compiler' not loaded!
- JIT compilation is discouraged for production use-cases! Consider AOT mode instead.
- Did you bootstrap using '@angular/platform-browser-dynamic' or '@angular/platform-server'?
- Alternatively provide the compiler with 'import "@angular/compiler";' before bootstrapping.
Error: Angular JIT compilation failed: '@angular/compiler' not loaded!
- JIT compilation is discouraged for production use-cases! Consider AOT mode instead.
- Did you bootstrap using '@angular/platform-browser-dynamic' or '@angular/platform-server'?
- Alternatively provide the compiler with 'import "@angular/compiler";' before bootstrapping.
at Ae (main.7000374ef126bad8069c.js:1)
at Function.get (main.7000374ef126bad8069c.js:1)
at St (main.7000374ef126bad8069c.js:1)
at new Af (main.7000374ef126bad8069c.js:1)
at ud (main.7000374ef126bad8069c.js:1)
at dd (main.7000374ef126bad8069c.js:1)
at e.md [as compileModuleAndAllComponentsAsync] (main.7000374ef126bad8069c.js:1)
at e. (main.7000374ef126bad8069c.js:1)
at Generator.next ()
at main.7000374ef126bad8069c.js:1
at T (polyfills.a8d522dff2c1a5c4b9db.js:1)
at polyfills.a8d522dff2c1a5c4b9db.js:1
at a (main.7000374ef126bad8069c.js:1)
at l.invoke (polyfills.a8d522dff2c1a5c4b9db.js:1)
at Object.onInvoke (main.7000374ef126bad8069c.js:1)
at l.invoke (polyfills.a8d522dff2c1a5c4b9db.js:1)
at i.run (polyfills.a8d522dff2c1a5c4b9db.js:1)
at polyfills.a8d522dff2c1a5c4b9db.js:1
at l.invokeTask (polyfills.a8d522dff2c1a5c4b9db.js:1)
at Object.onInvokeTask (main.7000374ef126bad8069c.js:1)
```

Commencez par retracer le chemin de build d’Angular CLI pour les builds optimisés et la manière dont il gère les imports utilisateur de @angular/compiler. Définissez l’achèvement comme la détection de cette combinaison pendant le build et le signalement d’un avertissement ou d’une erreur précis expliquant l’incompatibilité entre JIT et build-optimizer, ainsi que la correction disponible.

Rédigé par le modèle d'indexation à partir du texte de l'issue.