Adds the set-2038 test which sets the time to near-edge cases
like the start and end of the 32 bit epoch and checks that
time behaves properly. There is also a dangerous mode, which
lets the clock roll over past 2038 on 32bit systems, which
on some older kernels will cause system hangs.

Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Tested-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>