[Ada] Remove doubly-negated tests for empty lists

[Pierre-Marie de Rodat via Gcc-patches]

Replace "not Is_Non_Empty_List (...)" with "Is_Empty_List (...)".

Code cleanup; semantics is unaffected.

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

gcc/ada/

        * exp_ch5.adb (Update_Choice_Index): Simplify condition.
        * sem_ch8.adb (Attribute_Renaming): Likewise.
diff --git a/gcc/ada/exp_ch5.adb b/gcc/ada/exp_ch5.adb
--- a/gcc/ada/exp_ch5.adb
+++ b/gcc/ada/exp_ch5.adb
@@ -3563,8 +3563,7 @@ package body Exp_Ch5 is
                         --  is ok here.
                         --
                         pragma Assert
-                          (not Is_Non_Empty_List
-                                 (Component_Associations (Pattern)));
+                          (Is_Empty_List (Component_Associations (Pattern)));
 
                         declare
                            Agg_Length : constant Node_Id :=


diff --git a/gcc/ada/sem_ch8.adb b/gcc/ada/sem_ch8.adb
--- a/gcc/ada/sem_ch8.adb
+++ b/gcc/ada/sem_ch8.adb
@@ -4532,7 +4532,7 @@ package body Sem_Ch8 is
       --  have at least one formal parameter, with the exceptions of the GNAT
       --  attribute 'Img, which GNAT treats as renameable.
 
-      if not Is_Non_Empty_List (Parameter_Specifications (Spec)) then
+      if Is_Empty_List (Parameter_Specifications (Spec)) then
          if Aname /= Name_Img then
             Error_Msg_N
               ("subprogram renaming an attribute must have formals", N);