Update core CloneToUninit tests

Author: zachs18

library/core/tests/clone.rs

@@ -28,7 +28,7 @@ fn test_clone_to_uninit_slice_success() {
 
 letmut storage:MaybeUninit<[String;3]> = MaybeUninit::uninit();
 let b:[String;3] = unsafe{
- a[..].clone_to_uninit(storage.as_mut_ptr()as*mut[String]);
+ a[..].clone_to_uninit(storage.as_mut_ptr().cast());
  storage.assume_init()
 };
 
@@ -70,7 +70,7 @@ fn test_clone_to_uninit_slice_drops_on_panic() {
 letmut storage:MaybeUninit<[CountsDropsAndPanics;3]> = MaybeUninit::uninit();
 // This should panic halfway through
 unsafe{
- a[..].clone_to_uninit(storage.as_mut_ptr()as*mut[CountsDropsAndPanics]);
+ a[..].clone_to_uninit(storage.as_mut_ptr().cast());
 }
 })
 .unwrap_err();
@@ -89,13 +89,13 @@ fn test_clone_to_uninit_str() {
 let a = "hello";
 
 letmut storage:MaybeUninit<[u8;5]> = MaybeUninit::uninit();
-unsafe{ a.clone_to_uninit(storage.as_mut_ptr()as*mut[u8]as*mutstr)};
+unsafe{ a.clone_to_uninit(storage.as_mut_ptr().cast())};
 assert_eq!(a.as_bytes(),unsafe{ storage.assume_init()}.as_slice());
 
 letmut b:Box<str> = "world".into();
 assert_eq!(a.len(), b.len());
 assert_ne!(a,&*b);
-unsafe{ a.clone_to_uninit(ptr::from_mut::<str>(&mut b))};
+unsafe{ a.clone_to_uninit(ptr::from_mut::<str>(&mut b).cast())};
 assert_eq!(a,&*b);
 }
 
@@ -104,13 +104,13 @@ fn test_clone_to_uninit_cstr() {
 let a = c"hello";
 
 letmut storage:MaybeUninit<[u8;6]> = MaybeUninit::uninit();
-unsafe{ a.clone_to_uninit(storage.as_mut_ptr()as*mut[u8]as*mutCStr)};
+unsafe{ a.clone_to_uninit(storage.as_mut_ptr().cast())};
 assert_eq!(a.to_bytes_with_nul(),unsafe{ storage.assume_init()}.as_slice());
 
 letmut b:Box<CStr> = c"world".into();
 assert_eq!(a.count_bytes(), b.count_bytes());
 assert_ne!(a,&*b);
-unsafe{ a.clone_to_uninit(ptr::from_mut::<CStr>(&mut b))};
+unsafe{ a.clone_to_uninit(ptr::from_mut::<CStr>(&mut b).cast())};
 assert_eq!(a,&*b);
 }