[resend PATCH] ntdll: Tolerate null handle in DeregisterWait

[Marvin]

Hi,

While running your changed tests on Windows, I think I found new failures.
Being a bot and all I'm not very good at pattern recognition, so I might be
wrong, but could you please double-check?
Full results can be found at
https://testbot.winehq.org/JobDetails.pl?Key=25273

Your paranoid android.


=== w1064 (32 bit thread) ===
thread.c:1086: Test failed: got 0 with 5 (expected FALSE with ERROR_GEN_FAILURE)

=== w1064 (64 bit thread) ===
The test timed out