Temporarily add runAsync to run a task synchronously in the current thread

Add a temporary runtime entry to run a task synchronous.

Author: aschwaighofer

include/swift/Runtime/Concurrency.h

@@ -145,6 +145,10 @@ SWIFT_EXPORT_FROM(swift_Concurrency) SWIFT_CC(swift)
 NearestTaskDeadline
 swift_task_getNearestDeadline(AsyncTask *task);
 
+// TODO: Remove this hack.
+SWIFT_EXPORT_FROM(swift_Concurrency) SWIFT_CC(swift)
+void swift_task_run(AsyncTask *taskToRun);
+
 }
 
 #endif

stdlib/public/Concurrency/Task.cpp

@@ -132,3 +132,8 @@ swift::swift_task_create_f(JobFlags flags, AsyncTask *parent,
 
   return {task, initialContext};
 }
+
+// TODO: Remove this hack.
+void swift::swift_task_run(AsyncTask *taskToRun) {
+  taskToRun->run(ExecutorRef::noPreference());
+}

stdlib/public/Concurrency/Task.swift

@@ -306,3 +306,11 @@ extension Task {
     fatalError("\(#function) not implemented yet.")
   }
 }
+
+@_silgen_name("swift_task_run")
+public func runTask(_ task: __owned Builtin.NativeObject)
+
+public func runAsync(_ asyncFun: @escaping () async -> ()) {
+  let childTask = Builtin.createAsyncTask(0, nil, asyncFun)
+  runTask(childTask.0)
+}