[d8] Empty the foreground task queue before isolate shutdown

Tasks may contain Globals, which have to get destroyed before isolate
shutdown.

R=cbruni@chromium.org

Bug: chromium:1345081
Change-Id: I915baafd870c7bb8475b19736878179d8a22ca5a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3770108
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81840}

src/d8/d8.cc

@@ -3671,6 +3671,7 @@ void Shell::WriteLcovData(v8::Isolate* isolate, const char* file) {
 }
 
 void Shell::OnExit(v8::Isolate* isolate, bool dispose) {
+  platform::NotifyIsolateShutdown(g_default_platform, isolate);
   isolate->Dispose();
   if (shared_isolate) {
     i::Isolate::Delete(reinterpret_cast<i::Isolate*>(shared_isolate));