Fix timestamps recorded in Motif DND top level leave messages

* src/xterm.c (xm_send_top_level_leave_message): Use X_SHRT_MAX
since Motif treats x and y as signed.
(handle_one_xevent): Use correct time for lmsg.timestamp sent in
response to entering the return-frame.
2 jobs for master in 50 minutes and 21 seconds (queued for 7 seconds)
Status Job ID Name Coverage
  Build Images
failed #47795


skipped #47796
Name Stage Failure
build-image-inotify Build Images
net/http: request canceled (Client.Timeout exceeded while awaiting headers)
Running after_script
Running after script...
$ test -n "$(docker ps -aq -f name=${test_name})" && docker cp ${test_name}:checkout/test ${test_name}
$ test -n "$(docker ps -aq -f name=${test_name})" && docker rm ${test_name}
$ find ${test_name} ! \( -name "*.log" -o -name ${EMACS_TEST_JUNIT_REPORT} \) -type f -delete
find: build-image-inotify-3285901e: No such file or directory
Cleaning up project directory and file based variables
ERROR: Job failed: exit code 1