kernel: sched: bug fix for trace and monitor

sys_trace_thread_abort and z_thread_monitor_exit in
z_thread_single_abort also need to be protected by
sched_spinlock, otherwise when after the spinlock
release, if there is an pending interrupt, it will cause an
sched in the interrrupt exit, and those trace and monitor
function will never reach.

Signed-off-by: Watson Zeng <zhiwei@synopsys.com>