test: use assert() in N-API async test

The `Execute()` callback is not allowed to call into JS, so
we should use `assert()` instead of potentially throwing JS errors.

PR-URL: #28423
Fixes: nodejs/help#1998
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gabriel Schulhof <gabriel.schulhof@intel.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>

Author: addaleax

test/node-api/test_async/test_async.cc

@@ -1,3 +1,4 @@
+#include <assert.h>
 #include <stdio.h>
 #include <node_api.h>
 #include "../../js-native-api/common.h"
@@ -29,10 +30,7 @@ void Execute(napi_env env, void* data) {
 #endif
   carrier* c = static_cast<carrier*>(data);
 
-  if (c != &the_carrier) {
-    napi_throw_type_error(env, nullptr, "Wrong data parameter to Execute.");
-    return;
-  }
+  assert(c == &the_carrier);
 
   c->_output = c->_input * 2;
 }