MONITOR_IGNORE_NEW_THREAD added to the second return NULL of monitor_thread_pre_create
MONITOR_IGNORE_NEW_THREAD added to the second return NULL of monitor_thread_pre_create

(cherry picked from commit 186174a1ae727c745737aadf02cc4d6582261d48)

HPCToolkit/hpctoolkit,HPCToolkit/hpctoolkit,HPCToolkit/hpctoolkit,HPCToolkit/hpctoolkit,HPCToolkit/hpctoolkit,HPCToolkit/hpctoolkit