Fix hanging issue in _XReply

Assume event queue is empty if another thread is blocking waiting for event.

If one thread was blocking waiting for an event and another thread sent a
reply to the X server, both threads got blocked until an event was
received.

Signed-off-by: Tatu Frisk <tatu.frisk@ge.com>
Signed-off-by: Jose Alarcon <jose.alarcon@ge.com>
4 jobs for thread in 9 minutes and 44 seconds (queued for 45 seconds)
latest
Status Job ID Name Coverage
  Prep
passed check-commits #12248128

00:00:32

passed container-prep #12248129

00:01:27

 
  Build
passed build #12248130

00:07:40

 
  Deploy
passed check-merge-request #12248131

00:00:34