Move TSan release edge to swift_task_enqueueGlobal()

Move the TSan release edge from `swift_task_create_commonImpl()` to
`swift_task_enqueueGlobalImpl()`.  Task creation itself is not an event
that needs synchronization, but rather that task creation "happens
before" execution of that task on another thread.

This edge is usually added when the task is scheduled via
`swift_task_enqueue()` (which then usually calls
`swift_task_enqueueGlobal()`).  However, not all task scheduling goes
through the `swift_task_enqueue()` funnel as some places call the more
specific `swift_task_enqueueGlobal()` directly.  So let's annotate this
function (duplicate edges aren't harmful) to ensure we cover all
schedule events, including newly-created tasks (our original problem
here).

rdar://78932849
(cherry picked from commit e4e941e)

Author: Julian Lettner

stdlib/public/Concurrency/GlobalExecutor.cpp

@@ -335,6 +335,8 @@ static void swift_task_enqueueGlobalImpl(Job *job) {
 }
 
 void swift::swift_task_enqueueGlobal(Job *job) {
+  _swift_tsan_release(job);
+
   if (swift_task_enqueueGlobal_hook)
     swift_task_enqueueGlobal_hook(job, swift_task_enqueueGlobalImpl);
   else