tests: add threads scheduling test case with unified kernel

this commit cover thread scheduling relevant apis

k_current_get()
k_sched_lock()
k_sched_unlock()
k_yield()
k_sleep()
k_wakeup()
k_busy_wait()
k_sched_time_slice_set()

Change-Id: Ie449db3dda910bc1bafc0b5a04633f284e7f1dc3
Signed-off-by: jing wang <jing.j.wang@intel.com>
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
8 files changed