Mirigives subthreads a chance to join

Author: RalfJung

tokio/src/runtime/runtime.rs

@@ -431,7 +431,6 @@ impl Runtime {
     /// use std::time::Duration;
     ///
     /// fn main() {
-    /// #  if cfg!(miri) { return } // Miri reports error when main thread terminated without waiting all remaining threads.
     ///    let runtime = Runtime::new().unwrap();
     ///
     ///    runtime.block_on(async move {