[Ada] Preelaborate rules not fully enforced

[Pierre-Marie de Rodat]

In particular RM10.2.1(8) states:

    5 An elaborable construct is preelaborable unless its elaboration
    performs any of the following actions:

    ...

    8 The evaluation of a primary that is a name of an object, unless
    the name is a static expression, or statically denotes a
    discriminant of an enclosing type.

which isn't enforced in the case of an object referenced in a range, as
in:

   S : String (1 .. X);

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

gcc/ada/

        * sem_cat.adb (Is_Primary): Handle N_Range properly.
diff --git a/gcc/ada/sem_cat.adb b/gcc/ada/sem_cat.adb
--- a/gcc/ada/sem_cat.adb
+++ b/gcc/ada/sem_cat.adb
@@ -2121,6 +2121,7 @@ package body Sem_Cat is
                | N_Index_Or_Discriminant_Constraint
                | N_Membership_Test
                | N_Op
+               | N_Range
             =>
                return True;