This also fixes issues where the no_critical_edges flag was not cleared.

We first have to create the new replacement store after the phi, so the
following removal of the old nodes does not assume the ptr input value is
unused and kills it.

All users of NEW_ARR_A used it to construct a simple array, yet noone
cared about it actually being an array with a length field in front. For
this simple use case you should use ALLOCAN.

This seems to be done by a lot of projects out there while our previous
Q= seems to be exotic, so we additionally support V=1 now too.
(based on a patch from lu_zero@gentoo.org

This fixes backend/lower_call4.c (issue #113).

This avoids the deprecated u''.