v4.x backport: test,doc: clarify `buf.indexOf(num)` input range
Backport what is applicable of https://github.com/nodejs/node/pull/7611 to v4.x
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Backport what is applicable of https://github.com/nodejs/node/pull/7611 to v4.x