Support ("") as being equal to None in compare_property_list_of_ast_nodes.

src/compare/compare_field.rs

@@ -353,6 +353,15 @@ where
     let rust_value: Option<Vec<RV>> = rust_value.map(|it| it.collect());
     match (value, rust_value) {
         (None, None) => {}
+        (Some(el), None)
+            if el.len() == 1
+                && el.into_iter().all(|t| {
+                    if let Ok(r#""""#) = t.as_atom() {
+                        true
+                    } else {
+                        false
+                    }
+                }) => {}
         (None, rv @ Some(_)) | (Some(_), rv @ None) => {
             let this_status = DiffStatus::Bad;
             let message = Some(format!(