More tweaks from gimple_outgoing_range changes.

More tweaks from gimple_outgoing_range changes.

the dom_ranger used for fast vrp no longer needs a local
gimple_outgoing_range object as it is now always available from the
range_query parent class.

The builtin_unreachable code for adjusting globals and removing the
builtin calls during the final VRP pass can now function with just
a range_query object rather than a specific ranger.   This adjusts it to
use the extra methods in the range_query API.
This will now allow removal of builtin_unreachable calls even if there is no
active ranger with dependency info available.

	* gimple-range.cc (dom_ranger::dom_ranger): Do not initialize m_out.
	(dom_ranger::maybe_push_edge): Use gori () rather than m_out.
	* gimple-range.h (dom_ranger::m_out): Remove.
	* tree-vrp.cc (remove_unreachable::remove_unreachable): Use a
	range-query ranther than a gimple_ranger.
	(remove_unreachable::remove): New.
	(remove_unreachable::m_ranger): Change to a range_query.
	(remove_unreachable::handle_early): If there is no dependency
	information, do nothing.
	(remove_unreachable::remove_and_update_globals): Do not update
	globals if there is no dependecy info to use.