when sleep is called from root context (not within a task), it was
instantly advancing the simulated tick counter instead of actually
delaying. this caused task_pass.rb example to run tasks 0-5 instantly
without proper delays between iterations.
fixed by using clock_gettime() to track elapsed real time and sleeping
in 1ms intervals. also clear switching_ flag when returning from root
context sleep to prevent unwanted context switches.
removed find_earliest_wakeup_tick() function and time-advancing logic
from task_run_one_iteration() as real delays are now handled by sleep
itself.
Co-authored-by: Claude <noreply@anthropic.com>
Yukihiro "Matz" Matsumoto