Move the safety check performed by
_CORE_mutex_Check_dispatch_for_seize() out of the performance critical
path and generalize it. Blocking on a thread queue with an unexpected
thread dispatch disabled level is illegal in all system states.
Add the expected thread dispatch disable level (which may be 1 or 2
depending on the operation) to Thread_queue_Context and use it in
_Thread_queue_Enqueue_critical().