(v8.x backport) test: use ES6 classes instead of util.inherits
This is an early backport of https://github.com/nodejs/node/pull/16938 for node 8.x.
Affected core subsystem(s)
test
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
This is an early backport of https://github.com/nodejs/node/pull/16938 for node 8.x.
test