Update the event loop's time after executing a task

Update the event loop's time after executing a task

Tasks can block for a long time, especially when used by tools in
interactive mode. Update the event loop's time to avoid unexpected
errors when processing later events during the same callback.
For example, newly started timers can fire too early, because the
current time was stale. See the note about uv_update_time() in the
https://docs.libuv.org/en/v1.x/timer.html#c.uv_timer_start page.