Update testcases for illegal pointer casts

Author: Ulrik Sverdrup

src/test/compile-fail/issue-22034.rs

@@ -14,6 +14,6 @@ fn main() {
     let foo: *mut libc::c_void;
     let cb: &mut Fn() = unsafe {
         &mut *(foo as *mut Fn())
-        //~^ ERROR use of possibly uninitialized variable: `foo`
+        //~^ ERROR illegal cast
     };
 }

src/test/compile-fail/issue-22289.rs

@@ -9,5 +9,5 @@
 // except according to those terms.
 
 fn main() {
-    0 as &std::any::Any; //~ ERROR non-scalar cast: `i32` as `&core::any::Any`
+    0 as &std::any::Any; //~ ERROR illegal cast
 }