Implement more of the UTS#35 spec.

- Support for "tiny" weekdays and months (EEEEE and MMMMM)
- Support for standalone weekdays and months.
- Proper support for the 'Z' specifier (RFC-822 timezones)

Also fixes a bug in how date+time patterns were generated and
makes several unit tests clearer by using assertEquals instead
of assertTrue.

Fixes most of our DateFormat / SimpleDateFormat related tests.

bug: 25859156
bug: 25863120

Change-Id: Ieec88a29ddbd8ea8076e8913dfad1330d7ad4c25
4 files changed