fix tests

src/test/ui/consts/const-eval/ub-nonnull.rs

 #![feature(rustc_attrs, const_transmute)]
-#![allow(const_err)] // make sure we cannot allow away the errors tested here
+#![allow(const_err, invalid_value)] // make sure we cannot allow away the errors tested here
 
 use std::mem;
 use std::ptr::NonNull;

src/test/ui/consts/const-eval/ub-ref.rs

 // ignore-tidy-linelength
 #![feature(const_transmute)]
-#![allow(const_err)] // make sure we cannot allow away the errors tested here
+#![allow(const_err, invalid_value)] // make sure we cannot allow away the errors tested here
 
 use std::mem;
 

src/test/ui/consts/const-eval/ub-upvars.rs

 #![feature(const_transmute)]
-#![allow(const_err)] // make sure we cannot allow away the errors tested here
+#![allow(const_err, invalid_value)] // make sure we cannot allow away the errors tested here
 
 use std::mem;