add license text

Author: RalfJung

src/test/ui/const-eval/match-test-ptr-null.rs

@@ -1,3 +1,13 @@
+// Copyright 2018 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.
+
 fn main() {
     // Make sure match uses the usual pointer comparison code path -- i.e., it should complain
     // that pointer comparison is disallowed, not that parts of a pointer are accessed as raw