known breakage: revision range computation with clock skew

known breakage: revision range computation with clock skew

This is the absolute minimum (and reliable) reproduction recipe
to demonstrate that revision range in a history with clock skew
sometimes fails to mark UNINTERESTING commit in topologically
early parts of the history.

The history looks like this:

	o---o---o---o
	one         four

but one has the largest timestamp.  "git rev-list four..one"
fails to notice that "one" should not be emitted.

Signed-off-by: Junio C Hamano <gitster@pobox.com>