Fixed variable name used in translation cache
merged branch cedric-g/patch_translator (PR #8310)

This PR was submitted for the 2.3 branch but it was merged into the 2.2 branch instead (closes #8310).

Discussion
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[FrameworkBundle] Fixed variable name used in translation cache

This simply fixes the `$catalogueXXX` variable name used in the translation cache files in case the user use locales such as `en-US`, the generated variable's name was `$catalogueEn-Us`, with this fix it will be `$catalogueEnUs`.

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #7824
| License       | MIT
| Doc PR        | -

Commits
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e50399c [FrameworkBundle] Fixed variable name used in translation cache