add component-model-async/lift.wast test

This is another piece of bytecodealliance#9582 which I'm splitting out to make review easier.

This test includes two components: one which exports a function using the
async-with-callback ABI, and another which uses the async-without-callback ABI.
It doesn't actually instantiate or run either component yet.

The rest of the changes fill in some TODOs to make the test pass.

Signed-off-by: Joel Dice <[email protected]>

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

@@ -385,6 +385,15 @@ impl ComponentInstance {
         }
     }
 
+    /// Same as `set_runtime_memory` but for async callback function pointers.
+    pub fn set_runtime_callback(&mut self, idx: RuntimeCallbackIndex, ptr: NonNull<VMFuncRef>) {
+        unsafe {
+            let storage = self.vmctx_plus_offset_mut(self.offsets.runtime_callback(idx));
+            debug_assert!(*storage as usize == INVALID_PTR);
+            *storage = ptr.as_ptr();
+        }
+    }
+
     /// Same as `set_runtime_memory` but for post-return function pointers.
     pub fn set_runtime_post_return(
         &mut self,