[avalanche] Reject votes that fromnodes which already are in the quorum.

Summary:
This ensure we do not poll the same node again and again. By ensuring the quorum is diverse and that we do not have too many requests in flight, we ensure that we do not run ahead o the network.

Depends on D2583 and D2585

Test Plan: Added tests cases

Reviewers: #bitcoin_abc, jasonbcox

Reviewed By: #bitcoin_abc, jasonbcox

Subscribers: jasonbcox, teamcity, schancel

Differential Revision: https://reviews.bitcoinabc.org/D2586