udevadm-test: add missing oom check

src/udev/udevadm-test.c

@@ -130,6 +130,10 @@ int test_main(int argc, char *argv[], void *userdata) {
         device_seal(dev);
 
         event = udev_event_new(dev, NULL, EVENT_UDEVADM_TEST);
+        if (!event) {
+                log_oom();
+                goto out;
+        }
 
         assert_se(sigfillset(&mask) >= 0);
         assert_se(sigprocmask(SIG_SETMASK, &mask, &sigmask_orig) >= 0);