* Without an explicit format string, moment() should be called with
ISO date(times).
* Correctly destroy all test locales (`zz` was not destroyed at all,
and `englishForTest` was double-destroyed instead of destroying
`frenchForTests`).
* Avoid creating a moment object from the value `false` in date(time)
fields.
* Disable the warning entirely in dates_tests, the contents are super
messy and weird.
Xavier Morel
053285afdc