[C++] Re-enable strftime locale test on Windows

ARROW-13168 enabled timezone support on Windows, but found there was an issue with the vendored datetime library that caused invalid UTF-8 character to be emitted from strftime in certain locales. We should re-enable that test once we are able to get a fix in the date library (or some other solution is found).

https://github.com/HowardHinnant/date/issues/726

**Reporter**: [Will Jones](https://issues.apache.org/jira/browse/ARROW-15922) / @wjones127

_{**Note**: *This issue was originally created as [ARROW-15922](https://issues.apache.org/jira/browse/ARROW-15922). Please see the [migration documentation](https://github.com/apache/arrow/issues/14542) for further details.*}

Start with the disabled Windows strftime locale test and the linked HowardHinnant/date issue 726 to understand the vendored datetime-library failure. Done means the underlying invalid UTF-8 problem has a fix or workaround and the locale test is re-enabled and passes on Windows.

Written by the indexing model from the issue text.