re-run loop for pending async_t reqs
fix running nw as node
Revert "re-run loop for pending async_t reqs"

This reverts commit 6329d29e32542a608a6fb710601c757244ef00d3.
force waking up loop with uv_async_send_nw

uv_async_send() is not a reliable way to wake up loop.
See libuv issue 1453