async_wrap: run destroy in uv_timer_t

Calling the destroy callbacks in a uv_idle_t causes a timing issue where
if a handle or request is closed then the class isn't deleted until
uv_close() callbacks are called (which happens after the poll phase).
This results in some destroy callbacks not being called just before the
application exits. So instead switch the destroy callbacks to be called
in a uv_timer_t with the timeout set to zero.

When uv_run() is called with UV_RUN_ONCE the final operation of the
event loop is to process all remaining timers. By setting the timeout to
zero it results in the destroy callbacks being processed after
uv_close() but before uv_run() returned. Processing the destroyed ids
that were previously missed.

Also, process the destroy_ids_list() in a do {} while() loop that makes
sure the vector is empty before returning. Which also makes running
clear() unnecessary.

Fixes: https://github.com/nodejs/node/issues/13262
PR-URL: https://github.com/nodejs/node/pull/13369


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Andreas Madsen <amwebdk@gmail.com>