ada: Fix wrong finalization of constrained subtype of unconstrained array type

ada: Fix wrong finalization of constrained subtype of unconstrained array type

Dynamically allocated objects of a constrained subtype of an unconstrained
array type with a controlled component type have not been properly finalized
since the first rewrite of the finalization machinery more than a decade
ago.  The reason is that the Finalize_Address routine is that of the base
type, which is unconstrained, and thus requires the bounds, which are not
present for the subtype in the allocation.

This is fixed by setting Is_Constr_Array_Subt_With_Bounds for allocators the
same way it is set for object declarations.  The rest is just refactoring.

gcc/ada/ChangeLog:

	* exp_ch7.adb (Shift_Address_For_Descriptor): New function.
	(Make_Address_For_Finalize): Call above function.
	(Make_Finalize_Address_Stmts): Likewise.
	* exp_util.ads (Is_Constr_Array_Subt_Of_Unc_With_Controlled): New
	predicate.
	* exp_util.adb (Is_Constr_Array_Subt_Of_Unc_With_Controlled): Ditto.
	(Remove_Side_Effects): Call above predicate.
	* sem_ch3.adb (Analyze_Object_Declaration): Likewise.
	* sem_ch4.adb (Analyze_Allocator): Allocate the bounds by setting
	Is_Constr_Array_Subt_With_Bounds when appropriate.