fix some issues with locale (replace "LANGUAGE" with "LC_ALL")

`LANGUAGE=C` is not enough, `LC_ALL=C` is needed as the environment
variable that overrides all the other localization settings.

e.g.
```bash
$ LANGUAGE=C id foobar
id: ‘foobar’: no such user

$ LC_ALL=C id foobar
id: 'foobar': no such user
```

* replace `LANGUAGE` with `LC_ALL` as environment variable in the tests
* fix the the date string of affected uutils
* replace `‘` and `’` with `'`

tests/by-util/test_users.rs

@@ -17,7 +17,7 @@ fn test_users_check_name() {
     #[allow(clippy::needless_borrow)]
     let expected = TestScenario::new(&util_name)
         .cmd_keepenv(util_name)
-        .env("LANGUAGE", "C")
+        .env("LC_ALL", "C")
         .succeeds()
         .stdout_move_str();