remove post-return bits from async result lift code

...at least until we've determined whether post-return options even make sense
for async-lifted exports.

Signed-off-by: Joel Dice <joel.dice@fermyon.com>

Author: dicej

crates/wasmtime/src/runtime/component/func.rs

@@ -1041,20 +1041,15 @@ fn lift_results<
     let FuncData {
         options,
         instance,
-        component_instance,
         ty,
         ..
     } = store.0[me];
 
     let instance = store.0[instance.0].as_ref().unwrap();
     let types = instance.component_types().clone();
     let instance_ptr = instance.instance_ptr();
-    let mut flags = instance.instance().instance_flags(component_instance);
-
-    store.0[me].post_return_arg = Some(ValRaw::i32(0));
 
     unsafe {
-        flags.set_needs_post_return(true);
         Ok(Some(Box::new(lift(
             &mut LiftContext::new(store.0, &options, &types, instance_ptr),
             InterfaceType::Tuple(types[ty].results),