This adds several internal flags to TP_WAIT object to support the
implementation:

* WT_EXECUTEONLYONCE: waits are re-queued unless it is set.

* WT_EXECUTEINWAITTHREAD: call the callback in the wait thread when set.

* WT_EXECUTEINIOTHREAD: call alertable NtWaitForMultipleObjects in wait
  thread when set, as well the callback in the wait thread, as for
  WT_EXECUTEINWAITTHREAD. The worker threads use non-alertable waits
  otherwise.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=47843Signed-off-by: Rémi Bernon <rbernon@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>