Add run-pass test for repeat-generic-slice feature

Author: GuillaumeGomez

src/liballoc/repeat-generic-slice.rs

@@ -0,0 +1,19 @@
+// 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.
+
+#![feature(repeat_generic_slice)]
+
+fn main() {
+    assert_eq!([1, 2].repeat(2), vec![1, 2, 1, 2]);
+    assert_eq!([1, 2, 3, 4].repeat(0), vec![]);
+    assert_eq!([1, 2, 3, 4].repeat(1), vec![1, 2, 3, 4]);
+    assert_eq!([1, 2, 3, 4].repeat(3),
+               vec![1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4]);
+}