bless missing tests

Author: RalfJung

src/test/ui/issues/issue-18294.rs

@@ -1,5 +1,5 @@
 fn main() {
     const X: u32 = 1;
-    const Y: usize = unsafe { &X as *const u32 as usize }; //~ ERROR is unstable
+    const Y: usize = unsafe { &X as *const u32 as usize }; //~ ERROR pointers cannot be cast to integers
     println!("{}", Y);
 }

src/test/ui/issues/issue-18294.stderr

@@ -1,12 +1,11 @@
-error[E0658]: casting pointers to integers in constants is unstable
+error: pointers cannot be cast to integers during const eval.
   --> $DIR/issue-18294.rs:3:31
    |
 LL |     const Y: usize = unsafe { &X as *const u32 as usize };
    |                               ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
-   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
+   = note: at compile-time, pointers do not have an integer value
+   = note: avoiding this restriction via `transmute`, `union`, or raw pointers leads to compile-time undefined behavior
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0658`.