src: make StreamBase prototype accessors robust

This PR makes the prototype accessors added by StreamBase::AddMethods
nonenumerable and checks the signatures in the accessors so they
throw instead of raising assertions when called with incompatible
receivers. They could be enumerated when inspecting the prototype
with util.inspect or the inspector protocol.

PR-URL: https://github.com/nodejs/node/pull/16860


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>