c++: CTAD from initializer list [PR106366]

c++: CTAD from initializer list [PR106366]

During CTAD, we currently perform the first phase of overload resolution
from [over.match.list] only if the class template has a list constructor.
But according to [over.match.class.deduct]/4 it should be enough to just
have a guide that looks like a list constructor (which is a more general
criterion in light of user-defined guides).

	PR c++/106366

gcc/cp/ChangeLog:

	* pt.cc (do_class_deduction): Don't consider TYPE_HAS_LIST_CTOR
	when setting try_list_ctor.  Reset args even when try_list_ctor
	is true and there are no list candidates.  Call resolve_args on
	the reset args.  Rename try_list_ctor to try_list_cand.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp1z/class-deduction112.C: New test.