Merge branch 'bugfix/yield_other_core_prio_check_fix' into 'master'

Fix interrupting task on other CPU that has lower prio than current task on current CPU

Fix for a very subtle bug introduced somewhere in december. This bug would cause a cross-core interrupt to only be sent if the activated task has a higher priority than the task currently running on *this* cpu, instead of on the other CPU.

See merge request !475