remove test for issue #26194 because it is now redundant

src/test/compile-fail/issue-26194.rs

@@ -1,18 +0,0 @@
-// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// 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.
-
-struct S(String);
-
-impl S {
-    fn f(self: *mut S) -> String { self.0 }
-    //~^ ERROR raw pointer `self` is unstable
-}
-
-fn main() { S("".to_owned()).f(); }