Minor: Property emission, move abstract check to template

Change-Id: Ib3149d4fd30ec7ca3f0fad986196b04599265e14

langkit/expressions/base.py

@@ -1230,8 +1230,7 @@ class PropertyDef(AbstractNodeData):
         with self.bind(), Self.bind_type(self.ast_node):
             with names.camel_with_underscores:
                 self.prop_decl = render('properties/decl_ada')
-                self.prop_def = ('' if self.abstract else
-                                 render('properties/def_ada'))
+                self.prop_def = render('properties/def_ada')
 
         base_prop = self.base_property()
         if base_prop and base_prop.type:

langkit/templates/properties/def_ada.mako

@@ -1,5 +1,6 @@
 ## vim: filetype=makoada
 
+% if not property.abstract:
 ${"overriding" if property.overriding else ""} function ${property.name}
   (${property.self_arg_name} :
    access ${Self.type.name()}_Type${"" if property.dispatching else "'Class"}
@@ -35,3 +36,4 @@ begin
    ${property.constructed_expr.render_pre()}
    return ${property.constructed_expr.render_expr()};
 end ${property.name};
+% endif