Remove non-focused memory leak in `std` doctest for Miri. · model-checking/verify-rust-std@294d87f

Original file line number	Diff line number	Diff line change
`@@ -35,6 +35,7 @@ impl WaitTimeoutResult {`
`35`	`35`	`/// let pair = Arc::new((Mutex::new(false), Condvar::new()));`
`36`	`36`	`/// let pair2 = Arc::clone(&pair);`
`37`	`37`	`///`
	`38`	`+ /// # let handle =`
`38`	`39`	`/// thread::spawn(move \|\| {`
`39`	`40`	`/// let (lock, cvar) = &*pair2;`
`40`	`41`	`///`
`@@ -58,6 +59,8 @@ impl WaitTimeoutResult {`
`58`	`59`	`/// break`
`59`	`60`	`/// }`
`60`	`61`	`/// }`
	`62`	`+ /// # // Prevent leaks for Miri.`
	`63`	`+ /// # let _ = handle.join();`
`61`	`64`	/// ```
`62`	`65`	`#[must_use]`
`63`	`66`	`#[stable(feature = "wait_timeout", since = "1.5.0")]`