sched: yield() don't fuck up the runtime of a yeilding thread

Add a flag to a resched_from_interrupt() that will ensure the "other"
thread will be run instead of the current one when it's called from
yield().

 - Delete the call to thread_runtime::set_local() and delete the function itslef.
 - Add a resched_from_interrupt() a parameter "called_from_yield" to indicate that it has to,
   first, choose the next thread to run from the runqueue and only then push the current thread
   into it.
 - Add yield() and resched_from_interrupt() a parameter to indicate the maximum amount of time
   the thread wants to be out from the CPU. This parameter is relevant in resched_from_interrupt()
   only if "called_from_yield" is set to true.

Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
dynamic_thread_priority: comment the printouts

Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>