fixed memory leaks in PathBuf::leak & OsString::leak tests

Author: its-the-shrimp

std/src/ffi/os_str/tests.rs

@@ -26,8 +26,10 @@ fn test_os_string_clear() {
 #[test]
 fn test_os_string_leak() {
     let os_string = OsString::from("have a cake");
+    let (len, cap) = (os_string.len(), os_string.capacity());
     let leaked = os_string.leak();
     assert_eq!(leaked.as_encoded_bytes(), b"have a cake");
+    unsafe { drop(String::from_raw_parts(leaked as *mut OsStr as _, len, cap)) }
 }
 
 #[test]

std/src/path/tests.rs

@@ -128,9 +128,12 @@ fn into() {
 
 #[test]
 fn test_pathbuf_leak() {
-    let buf = PathBuf::from("/have/a/cake".to_owned());
+    let string = "/have/a/cake".to_owned();
+    let (len, cap) = (string.len(), string.capacity());
+    let buf = PathBuf::from(string);
     let leaked = buf.leak();
     assert_eq!(leaked.as_os_str().as_encoded_bytes(), b"/have/a/cake");
+    unsafe { drop(String::from_raw_parts(leaked.as_mut_os_str() as *mut OsStr as _, len, cap)) }
 }
 
 #[test]