Fixed sort

[drstranges]

Hello.

There is some issue with random sort order of locales in generated files (i18n.dart and messages_all.dart).
Maybe platform related.
For example:
i18n.dart on Max OS:
return const [
Locale("en", ""),
Locale("uk", ""),
Locale("pl", ""),
Locale("ru", ""),
];
On Ubuntu:
return const [
Locale("en", ""),
Locale("ru", ""),
Locale("pl", ""),
Locale("uk", ""),
];

messages_all.dart - even worse.
We want this files to be included in git, instead of regenerate them each time we run build. So it would be great if sort could be fixed.