Adjust tests for newly added ambiguous_wide_pointer_comparisons lint

Author: Urgau

tests/pass/pointers.rs

@@ -2,6 +2,7 @@
 //@[tree]compile-flags: -Zmiri-tree-borrows
 //@compile-flags: -Zmiri-permissive-provenance
 #![feature(ptr_metadata, const_raw_ptr_comparison)]
+#![allow(ambiguous_wide_pointer_comparisons)]
 
 use std::mem::{self, transmute};
 use std::ptr;

tests/pass/rc.rs

@@ -3,6 +3,7 @@
 //@compile-flags: -Zmiri-strict-provenance
 #![feature(new_uninit)]
 #![feature(get_mut_unchecked)]
+#![allow(ambiguous_wide_pointer_comparisons)]
 
 use std::cell::{Cell, RefCell};
 use std::fmt::Debug;