[Ada] Fix range check on constrained array with expanded index name

[Pierre-Marie de Rodat]

When detecting a type name we must look for both identifiers and
expanded names.

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

gcc/ada/

        * sem_ch3.adb (Analyze_Subtype_Declaration): Recognize both
        identifiers and expanded names; use high-level Is_Scalar_Type
        instead of low-level membership test.
diff --git a/gcc/ada/sem_ch3.adb b/gcc/ada/sem_ch3.adb
--- a/gcc/ada/sem_ch3.adb
+++ b/gcc/ada/sem_ch3.adb
@@ -5829,8 +5829,8 @@ package body Sem_Ch3 is
                Target_Index := First_Index (Indic_Typ);
 
                while Present (Subt_Index) loop
-                  if ((Nkind (Subt_Index) = N_Identifier
-                        and then Ekind (Entity (Subt_Index)) in Scalar_Kind)
+                  if ((Nkind (Subt_Index) in N_Expanded_Name | N_Identifier
+                        and then Is_Scalar_Type (Entity (Subt_Index)))
                        or else Nkind (Subt_Index) = N_Subtype_Indication)
                     and then
                       Nkind (Scalar_Range (Etype (Subt_Index))) = N_Range