Skips test that need full lib-intl.
minor #9896 [Intl] Skip tests that need full lib-intl when there's no lib-intl (pamil)

This PR was submitted for the 2.3-dev branch but it was merged into the 2.3 branch instead (closes #9896).

Discussion
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[Intl] Skip tests that need full lib-intl when there's no lib-intl

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

`NumberFormatter::formatCurrency` executes indirectly `Symfony\Component\Intl\ResourceBundle\Reader::read()`, which has `$bundle = new \ResourceBundle($locale, $path)` - there's Fatal Error if `\ResourceBundle` isn't found. Added availability to run unit tests if `lib-intl` isn't installed.

Commits
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6614b66 Skips test that need full lib-intl.