[CHANGED] Randomize Leafnode remote URLs and add option to disable

[variadico]

Currently, leafnode remote URLs are kept in order when parsed. This change randomizes the order of URLs by default and adds an option to disable this behavior, returning you to the way it was before.

leafnodes {
  remotes = [
    {
      dont_randomize: true
      url: [
        "nats-leaf://host1:7422"
        "nats-leaf://host2:7422"
        "nats-leaf://host3:7422"
        "nats-leaf://host4:7422"
      ]
      account: fizzbuzz
      credentials: "./fizzbuzz.creds"
    }
  ]
}

Resolves #2153

/cc @nats-io/core

[matthiashanel]

@variadico @kozlovic , wondering if we should enable this by default and provide an option to turn it off. In part because this is the right thing to do, Why make it harder by having to enable the better behavior.

[ripienaar]

Agree. Should be default.

[kozlovic]

Yes, sorry I missed that too. Since I saw the discussion on Slack and issue reported by Don R., I assumed that this was the direction we would take. @variadico The flag would have to be a negative, like "NoSuffle" or something like that.

[variadico]

All right. Got some updates.

• Moved rand.Shuffle to validateLeafNode
• Made rand.Shuffle the default behavior
• Changed the name "shuffle" to "random" to match the term the NATS client uses (any thoughts on this?)
• Updated the parsing code
• Added new tests

[kozlovic]

LGTM!