Move vec-macro-repeat test

Author: poliorcetics

library/alloc/tests/vec.rs

@@ -1929,3 +1929,16 @@ fn test_zero_sized_vec_push() {
         tester.clear();
     }
 }
+
+#[test]
+fn test_vec_macro_repeat() {
+    assert_eq!(vec![1; 3], vec![1, 1, 1]);
+    assert_eq!(vec![1; 2], vec![1, 1]);
+    assert_eq!(vec![1; 1], vec![1]);
+    assert_eq!(vec![1; 0], vec![]);
+
+    // from_elem syntax (see RFC 832)
+    let el = Box::new(1);
+    let n = 3;
+    assert_eq!(vec![el; n], vec![Box::new(1), Box::new(1), Box::new(1)]);
+}