[Ada] Ada2020: AI12-0195 overriding class-wide pre/post conditions

[Ada] Ada2020: AI12-0195 overriding class-wide pre/post conditions

gcc/ada/

	* contracts.adb (Process_Spec_Postconditions): Add missing
	support for aliased subprograms and handle wrappers of
	class-wide pre/post conditions.
	(Process_Inherited_Preconditions): Add missing support for
	aliased subprograms and handle wrappers of class-wide pre/post
	conditions.
	* einfo.ads (Class_Wide_Clone): Fix typo.
	(Is_Class_Wide_Clone): Removed since it is not referenced.
	(Is_Wrapper): Documenting new flag.
	(LSP_Subprogram): Documenting new attribute.
	* exp_ch3.adb (Make_Controlling_Function_Wrappers): Decorate
	wrapper as Is_Wrapper and adjust call to
	Override_Dispatching_Operation.
	* freeze.adb (Build_Inherited_Condition_Pragmas): Fix typo in
	documentation.
	(Check_Inherited_Conditions): Handle LSP wrappers; ensure
	correct decoration of LSP wrappers.
	* gen_il-fields.ads (Is_Class_Wide_Clone): Removed.
	(Is_Wrapper): Added.
	(LSP_Subprogram): Added.
	* gen_il-gen-gen_entities.adb (Is_Class_Wide_Clone): Removed.
	(Is_Wrapper): Added.
	(LSP_Subprogram): Added.
	* gen_il-internals.adb (Image): Adding uppercase image of
	LSP_Subprogram.
	* sem_ch6.adb (New_Overloaded_Entity): Fix decoration of LSP
	wrappers.
	* sem_disp.ads (Override_Dispatching_Operation): Remove
	parameter Is_Wrapper; no longer needed.
	* sem_disp.adb (Check_Dispatching_Operation): Adjust assertion.
	(Override_Dispatching_Operation): Remove parameter Is_Wrapper;
	no longer needed.
	* treepr.adb (Image): Adding uppercase image of LSP_Subprogram.