refactor(gstd): use waker-fn instead of unsafe code

gstd/Cargo.toml

@@ -25,6 +25,7 @@ hex = { workspace = true, features = ["alloc"] }
 parity-scale-codec = { workspace = true, features = ["derive"] }
 scale-info = { workspace = true, features = ["derive"] }
 futures = { workspace = true, features = ["alloc"] }
+waker-fn = "1.2.0"
 
 [features]
 #! ## Default features

gstd/src/async_runtime/futures.rs

@@ -47,7 +47,7 @@ impl Task {
         F: Future<Output = ()> + 'static,
     {
         Self {
-            waker: super::waker::empty(),
+            waker: waker_fn::waker_fn(|| {}),
             future: future.boxed_local(),
             lock_exceeded: false,
         }

gstd/src/async_runtime/mod.rs

@@ -19,7 +19,6 @@
 mod futures;
 mod locks;
 mod signals;
-mod waker;
 
 #[cfg(not(feature = "ethexe"))]
 mod reply_hooks;