[Ada] Requires_Cleanup_Actions and N_Protected_Body

[Pierre-Marie de Rodat via Gcc-patches]

This patch disallows N_Protected_Body from being passed to
Requires_Cleanup_Actions. Protected bodies never need cleanup, and are
never passed to Requires_Cleanup_Actions, which is a good thing, because
it would blow up on Handled_Statement_Sequence, which doesn't exist for
N_Protected_Body.

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

gcc/ada/

        * exp_util.adb (Requires_Cleanup_Actions): Remove
        N_Protected_Body from the case statement, so that case will be
        covered by "raise Program_Error".
diff --git a/gcc/ada/exp_util.adb b/gcc/ada/exp_util.adb
--- a/gcc/ada/exp_util.adb
+++ b/gcc/ada/exp_util.adb
@@ -12781,7 +12781,6 @@ package body Exp_Util is
             | N_Block_Statement
             | N_Entry_Body
             | N_Package_Body
-            | N_Protected_Body
             | N_Subprogram_Body
             | N_Task_Body
          =>