efl: streamline DayselectorUserTest

Move the SUNDAY special case into the loop by using the modulo
operator to choose correct day selection and label.

Signed-off-by: U. Artie Eoff <ullysses.a.eoff@intel.com>
efl: test deselection in DayselectorUserTest, too

Signed-off-by: U. Artie Eoff <ullysses.a.eoff@intel.com>