[Form] fixed ChoiceListCache (made hash more unique)

this PR refers to this issue: https://github.com/symfony/symfony/issues/10027

*Especially naming in the unittests wasn't that easy for me. I'm open for any better suggestions.*

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | https://github.com/symfony/symfony/issues/10027
| License       | MIT
| Doc PR        | none