test: fix promise message test after V8 update

PR-URL: #19201
Reviewed-By: Ali Ijaz Sheikh <ofrobots@google.com>
Reviewed-By: Myles Borins <myles.borins@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

test/message/unhandled_promise_trace_warnings.out

@@ -34,6 +34,7 @@
     at *
 (node:*) PromiseRejectionHandledWarning: Promise rejection was handled asynchronously (rejection id: 1)
     at handledRejection (internal/process/promises.js:*)
+    at Promise.then *
     at Promise.catch *
     at Immediate.setImmediate (*test*message*unhandled_promise_trace_warnings.js:*)
     at *