core: Removed classes DateTimeStyles, CultureInfo, TimeFormatValidation

Removed the classes DateTimeStyles, CultureInfo, TimeFormatValidation
from the compat package, they are no longer needed and all using methods
had no references and were removed

Change-Id: I765a43e6c5e9a6fc176caedd8294b4b0168f39a6
Signed-off-by: Tal Nisan <tnisan@redhat.com>