We get the info for the underlying progression and invert it. For
progressions whose last bound was open (e.g., `until` loop), the
reversed version will have an open first bound and so the induction
variable must be incremented first.
Also unified the way of extracting HeaderInfo out of changed calls
(e.g., `indices.reversed()`), and fixed declaration parents in
ForLoopsLowering.
HeaderInfo object, and modifying the operator in the loop condition.
The "additional emptiness condition" is no longer necessary with this.
The open/closed property was removed from HeaderInfo in an earlier
commit, but bringing it back in to simplify the loop building makes
more sense.
Also expanded tests for evaluation order of range bounds.
Mark Punzalan