[d8] Pump message when waiting for TLA Promise

We might have to wait for background tasks to complete (e.g. when
awaiting ax  WebAssembly.instantiate) and not just other promises.

Bug: v8:12568
Change-Id: Ibf99074d7a3c924b77b7959006087a05d39ffd3b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3423777Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78871}

src/d8/d8.cc

@@ -1401,11 +1401,9 @@ bool Shell::ExecuteModule(Isolate* isolate, const char* file_name) {
   }
 
   // Loop until module execution finishes
-  // TODO(cbruni): This is a bit wonky. "Real" engines would not be
-  // able to just busy loop waiting for execution to finish.
   Local<Promise> result_promise(result.As<Promise>());
   while (result_promise->State() == Promise::kPending) {
-    isolate->PerformMicrotaskCheckpoint();
+    Shell::CompleteMessageLoop(isolate);
   }
 
   if (result_promise->State() == Promise::kRejected) {