Patterns API column for j.t.SimpleDateFormat javadoc

Since from 24+ we support 'u' pattern which was not supported
earlier, I've extended javadoc with Supported API column.

Added tests for the 'u' pattern.

Test: make docs, vogat SimpleDataFormatTest run
Bug: 31480620
Change-Id: I9dbb0ad5c978f8ea5b9b8444c5e06e8d91d2f5ad
2 files changed