test: turmoil: route openraft RNG and spawn through DeterministicRng

Override `AsyncRuntime` in the test's `TypeConfig` so openraft's
internal `thread_rng()` and `spawn` honor the per-host deterministic
seed already set up by `cluster.rs`.

`declare_raft_types!` defaults `AsyncRuntime` to plain `TokioRuntime`,
whose `thread_rng()` is `rand::rng()` (OS-seeded) and whose `spawn`
is `tokio::spawn`. Each host enters `DeterministicRng::scope`, but
plain runtime calls bypass the task-local `DETSIM_SEED` entirely —
election timeouts and child-task seeds came from the OS RNG, so the
cluster diverged across runs even after the prior fuzz-driver
determinism fix.

`DeterministicRng<TokioRuntime>` routes both `thread_rng()` and
`spawn` through the wrapper that consults `DETSIM_SEED`, completing
the determinism story for `--reproduce`.

Author: drmingdrmer

tests-turmoil/src/typ.rs

@@ -49,6 +49,7 @@ openraft::declare_raft_types!(
         D = Request,
         R = Response,
         Node = Node,
+        AsyncRuntime = openraft_rt::deterministic_rng::DeterministicRng<openraft_rt_tokio::TokioRuntime>,
 );
 
 pub type Raft = openraft::Raft<TypeConfig, std::sync::Arc<crate::store::StateMachine>>;