[Ada] Inconsistency between declaration and body of predicate functions

[Ada] Inconsistency between declaration and body of predicate functions

gcc/ada/

	* sem_ch13.adb (Resolve_Aspect_Expressions): Use the same
	processing for Predicate, Static_Predicate and
	Dynamic_Predicate. Do not build the predicate function spec.
	Update comments.
	(Resolve_Name): Only reset Entity when necessary to avoid
	spurious visibility errors.
	(Check_Aspect_At_End_Of_Declarations): Handle consistently all
	Predicate aspects.
	* sem_ch3.adb (Analyze_Subtype_Declaration): Fix handling of
	private types with predicates.