[Ada] Double evaluation of predicate

[Pierre-Marie de Rodat]

In some case involving a type with a predicate and an inner package with
a subprogram referencing the type, GNAT would call Add_Predicate twice
on the same pragma node, causing tree sharing conflicts.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

        * sem_ch13.adb (Add_Predicates): Prevent analyzing twice the
        same pragma in case an inner package references the type with a
        predicate (as opposed to defining the type).
diff --git a/gcc/ada/sem_ch13.adb b/gcc/ada/sem_ch13.adb
--- a/gcc/ada/sem_ch13.adb
+++ b/gcc/ada/sem_ch13.adb
@@ -9746,7 +9746,7 @@ package body Sem_Ch13 is
 
             elsif Nkind (Ritem) = N_Aspect_Specification
               and then Present (Aspect_Rep_Item (Ritem))
-              and then Scope (Typ) /= Current_Scope
+              and then Scope_Depth (Scope (Typ)) > Scope_Depth (Current_Scope)
             then
                declare
                   Prag : constant Node_Id := Aspect_Rep_Item (Ritem);