src: add missing Isolate arguments

Reviewed-by: Trevor Norris <trev.norris@gmail.com>
node: add missing Isolate::Scope at startup

Reviewed-by: Trevor Norris <trev.norris@gmail.com>
dns: throw if hostname is not string or falsey

Fix assertion failure from poor argument parsing logic introduced in
6ea5d16. Add tests to make sure arguments are properly parsed.

Fixes: 6ea5d16 "dns: always set variable family in lookup()"
Reviewed-by: Trevor Norris <trev.norris@gmail.com>
net,stream: add isPaused, don't read() when paused

net Sockets were calling read(0) to start reading, without
checking to see if they were paused first. This would result
in paused Socket objects keeping the event loop alive.

Fixes #8200

Reviewed-by: Trevor Norris <trev.norris@gmail.com>
http: avoid create difference hidden class

Reviewed-by: Trevor Norris <trev.norris@gmail.com>