Creating such objects (without using them for the UI) is supported under
all platforms, so allow doing it.
Note that this is only supported under Unix systems when locale_t and
related functionality is available, but this should be the case just
about everywhere by now.
Add a test (or, rather, replace an existing test which was disabled by
default) checking that we can now get locale information about any
locale, not necessarily the currently used one.
45f9908e05