MFC r359585, r359587

r359585:
Fix calculation of the recurring weekdays

Both the result of the first_dayofweek_of_year and the target
weekday are zero-based (0 fo sunday) while the target month-day
or year-day is 1-based. Adjust logic accordingly.

Also add testcase for this PR to the kyua test suite

PR: 201062
Submitted by: Richard Narron <comet.berkeley@gmail.com>

r359587:
Remove hardcoded US Election Day from calendar.usholiday

calendar(1) syntax is not capable of representing the rules for the
US Election Day. The hardcoded date was set in r15066 in 1996 and
hasn't changed since then.

PR: 173389
Reported by: Steve Ames <steve@energistic.com>