Fix rare crash when async input happens while creating xm drag window

* src/xterm.c (xm_get_drag_window): Work around XCloseDisplay
freezing upon being interrupted by a signal.
2 jobs for master in 75 minutes and 44 seconds (queued for 6 seconds)
Status Job ID Name Coverage
  Build Images
failed #46660
build-image-inotify

01:15:44

 
  Normal
skipped #46661
test-src-inotify
 
Name Stage Failure
failed
build-image-inotify Build Images
executor failed running [/bin/sh -c make bootstrap]: exit code: 2
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-760fd430: No such file or directory
Cleaning up project directory and file based variables
ERROR: Job failed: exit code 1