[FrameworkBundle] remove invalid tests

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | 
| License       | MIT
| Doc PR        | 

With #12046, the `getLocale()` method isn't overriden anymore by the `Translator` from the FrameworkBundle, but the locale is set by the new `TranslatorListener`. Therefore, the tests ensuring the old behavior are removed.