src: ensure no more platform foreground tasks after Deinit

Node first calls `Isolate::Dispose`, then `NodePlatform::UnregisterIsolate`. This again calls `PerIsolatePlatformData::Shutdown`, which (before this patch) called `FlushForegroundTasksInternal`, which might call `RunForegroundTask` if it finds foreground tasks to be executed. This will fail however, since `Isolate::GetCurrent` was already reset during `Isolate::Dispose`. Hence remove the check to `FlushForegroundTasksInternal` and add checks instead that no more foreground tasks are scheduled. Refs: v8#86 PR-URL: #25653 Reviewed-By: Gus Caplan <[email protected]> Reviewed-By: Colin Ihrig <[email protected]>

Author: backes

src/node_platform.cc

@@ -265,7 +265,8 @@ void PerIsolatePlatformData::Shutdown(){
 if (flush_tasks_ == nullptr)
 return;
 
-while (FlushForegroundTasksInternal()){}
+CHECK_NULL(foreground_delayed_tasks_.Pop());
+CHECK_NULL(foreground_tasks_.Pop());
 CancelPendingDelayedTasks();
 
 uv_close(reinterpret_cast<uv_handle_t*>(flush_tasks_),