c++: Move hidden-lambda entity lookup checking

c++: Move hidden-lambda entity lookup checking

Hidden lambda entities only occur in block and class scopes.  There's
no need to check for them on every lookup.  So moving that particular
piece of validation to lookup_name_1, which cares.  Also reordered the
namespace and type checking, as that is also simpler.

	gcc/cp/
	* name-lookup.c (qualify_lookup): Drop lambda checking here.
	Reorder namespace & type checking.
	(lookup_name_1): Do hidden lambda checking here.