AJCORE-310 Fix race condition in Event::Wait implementation in windows.
If return value from WaitForMultipleObjectsEx indicates that a handle is
set but signaledEvents is empty, this is a spurious return value.
Loop back and call WaitForMultipleObjectsEx again in this case.

Change-Id: I6b6d02c39098971ddeb8c6d5883ea05e9fae300d