Remove obsolete compile-fail test

test_suite/tests/compile-fail/identifier/not_identifier.rs

@@ -1,20 +0,0 @@
-// Copyright 2017 Serde Developers
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-#[macro_use]
-extern crate serde_derive;
-
-#[derive(Deserialize)]
-enum F {
-    A,
-    #[serde(other)]
-    //~^^^^ ERROR: #[serde(other)] may only be used inside a field_identifier
-    B,
-}
-
-fn main() {}