collections: Fix drain test names

Author: Ulrik Sverdrup

src/libcollectionstest/vec.rs

@@ -491,13 +491,13 @@ fn test_drain_items_zero_sized() {
 
 #[test]
 #[should_panic]
-fn drain_out_of_bounds_1() {
+fn test_drain_out_of_bounds() {
     let mut v = vec![1, 2, 3, 4, 5];
     v.drain(5..6);
 }
 
 #[test]
-fn drain_range() {
+fn test_drain_range() {
     let mut v = vec![1, 2, 3, 4, 5];
     for _ in v.drain(4..) {
     }