Remove recursion from range_from_dom.

Remove recursion from range_from_dom.

Avoid calling range_of_dom recursively by putting all nodes to be
calculated on the worklist, and figure out which kind they are
when removed from the list.

	* gimple-range-cache.cc (ranger_cache::resolve_dom): New.
	(ranger_cache::range_from_dom): Put all nodes to be calculated
	in the worklist and resolve after the dom walk.
	* gimple-range-cache.h (resolve_dom): New prototype.