c++: Immediately deduce auto member [PR94926].

c++: Immediately deduce auto member [PR94926].

In r9-297 I was trying to be more flexible and treat static data members of
class templates more like variable templates, where the type need not be
determined until the variable is instantiated, but I suppose that in a class
the types of all the non-template members need to be determined at the time
of class instantiation.

gcc/cp/ChangeLog:

	PR c++/94926
	* decl.c (cp_finish_decl): Revert r9-297 change.
	(check_static_variable_definition): Likewise.
	* constexpr.c (ensure_literal_type_for_constexpr_object): Likewise.
	* pt.c (instantiate_decl): Return early on type error.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp1z/pr86648.C: Expect error.
	* g++.dg/cpp1z/static2.C: Expect error.
	* g++.dg/cpp0x/nsdmi16.C: New test.