fs,net: emit 'ready' for fs streams and sockets

... in addition to the event names they currently use.

Currently, various internal streams have different events that
indicate that the underlying resource has successfully been
established. This commit adds ready event for fs and net
sockets to standardize on emitting ready for all of these streams.

PR-URL: https://github.com/nodejs/node/pull/19408
Fixes: https://github.com/nodejs/node/issues/19304


Reviewed-By: Anna Henningsen <anna@addaleax.net>