[Ada] Remove dead code for scope entity having E_Subprogram_Body kind

[Pierre-Marie de Rodat via Gcc-patches]

In GNAT AST the Scope field always points to the semantic scope (e.g.
subprogram) and never to syntactic scope (e.g. subprogram body).

Cleanup related to handling of circular access-to-record types.

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

gcc/ada/

        * gcc-interface/decl.cc (gnat_to_gnu_entity): Remove dead code
        which expected Scope to return E_Subprogram_Body entity.
diff --git a/gcc/ada/gcc-interface/decl.cc b/gcc/ada/gcc-interface/decl.cc
--- a/gcc/ada/gcc-interface/decl.cc
+++ b/gcc/ada/gcc-interface/decl.cc
@@ -363,10 +363,6 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, bool definition)
 	  if (Is_Type (gnat_temp))
 	    gnat_temp = Underlying_Type (gnat_temp);
 
-	  if (Ekind (gnat_temp) == E_Subprogram_Body)
-	    gnat_temp
-	      = Corresponding_Spec (Parent (Declaration_Node (gnat_temp)));
-
 	  if (Is_Subprogram (gnat_temp)
 	      && Present (Protected_Body_Subprogram (gnat_temp)))
 	    gnat_temp = Protected_Body_Subprogram (gnat_temp);