Include 'handled_hint' when printing JSPromise objects

R=bmeurer@chromium.org

Change-Id: I7338c4a5a259b7f81e8f7719d29c41e721ec1b00
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1921795
Auto-Submit: Simon Zünd <szuend@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65012}

src/diagnostics/objects-printer.cc

@@ -654,6 +654,7 @@ void JSPromise::JSPromisePrint(std::ostream& os) {  // NOLINT
     os << "\n - result: " << Brief(result());
   }
   os << "\n - has_handler: " << has_handler();
+  os << "\n - handled_hint: " << handled_hint();
   JSObjectPrintBody(os, *this);
 }