Bug: runtime spawn_batch does not release permit correctly

[dantengsky]

Summary

on behalf of @Xuanwo

in runtime try_spawn_batch

            let handler = self.handle.spawn(async move {
                // take the ownership of the permit, (implicitly) drop it when task is done
                let _ = permit;  // <- compiler will drop permit here, instead of at the end of async block
                fut.await
            });

[BohuTANG]

Fixed in 1e59548
Merged to the main branch.

[dantengsky]

addressed in pr #8153