sync::mpsc: add miri reproducer of double free

Signed-off-by: Petros Angelatos <[email protected]>

Author: petrosagg

library/std/src/sync/mpmc/list.rs

@@ -213,6 +213,8 @@ impl<T> Channel<T> {
                     .compare_exchange(block, new, Ordering::Release, Ordering::Relaxed)
                     .is_ok()
                 {
+                    #[cfg(miri)]
+                    crate::thread::yield_now();
                     self.head.block.store(new, Ordering::Release);
                     block = new;
                 } else {

src/tools/miri/tests/pass/concurrency/issue139553.rs

@@ -0,0 +1,15 @@
+//@compile-flags: -Zmiri-preemption-rate=0 -Zmiri-compare-exchange-weak-failure-rate=0
+use std::sync::mpsc::channel;
+use std::thread;
+
+pub fn main() {
+    let (s1, r) = channel::<u64>();
+    let s2 = s1.clone();
+    let t1 = thread::spawn(move || {
+        let _ = s1.send(42);
+    });
+    std::thread::yield_now();
+    s2.send(42).unwrap();
+    drop(r);
+    t1.join().unwrap();
+}