async_wrap: add constructor for PromiseWrap

Another optional argument is about to be added to AsyncWrap. So instead
of piling them on, create a separate constructor specifically for
PromiseWrap since it's the only class that uses the "silent" argument.

PR-URL: https://github.com/nodejs/node/pull/14208


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>