Rollup merge of rust-lang#122016 - RalfJung:will_wake, r=dtolnay

will_wake tests fail on Miri and that is expected

Follow-up to rust-lang#121622
r? ```@cuviper``` ```@dtolnay```

library/alloc/tests/task.rs

@@ -4,6 +4,7 @@ use alloc::task::{LocalWake, Wake};
 use core::task::{LocalWaker, Waker};
 
 #[test]
+#[cfg_attr(miri, should_panic)] // `will_wake` doesn't guarantee that this test will work, and indeed on Miri it fails
 fn test_waker_will_wake_clone() {
     struct NoopWaker;
 
@@ -19,6 +20,7 @@ fn test_waker_will_wake_clone() {
 }
 
 #[test]
+#[cfg_attr(miri, should_panic)] // `will_wake` doesn't guarantee that this test will work, and indeed on Miri it fails
 fn test_local_waker_will_wake_clone() {
     struct NoopWaker;