[improve][broker]improve the getAntiAffinityNamespaceOwnedBrokers check exclude the current namespace cause count add.

[Nicklee007]

Motivation

As the PIP 7: Pulsar Failure domain and Anti affinity namespaces design, the anti affinity namespaces should be distributed to evenly across all domain and all the brokers.
But in method getAntiAffinityNamespaceOwnedBrokers , brokerToAntiAffinityNamespaceCount add a count even the namespace equal the given bundle's namespace which will be load. The behavior will cause the namespace easy to distributed to
a broker which has another namespace in anti affinity group, the behavior broke the anti affinity balance. It's better behavior is the same namespace should be distributed to those broker which has loaded the same namespace when all broker have load at least one namespace in ti affinity group.

there is some case
ns-0 ns-1 ns-2 are all set the same anti affinity group like 'a-group

broker-0 own ns-0 bundle-0;
broker-1 own ns-1 bundle-0;
broker-2 own ns-2 bundle-0;
then another ns-2 bundle-1 need choice a broker to load. As the old policy, broker-0 broker-1 and broker-2 are all satisfy the least NamespaceCount; but if ns-2 bundle-1 load to broker-0 or broker-1 will broke the anti affinity balance. ns-2 bundle-1 need be load by broker-2 is better.

Also, the behavior will cause give up doLoadShedding when the all broker own one namespace in anti affinity group, but the different broker owned namespace bundle count and payload is different.
So brokerToAntiAffinityNamespaceCount should exclude the given namespace count add.

Modifications

1. In LoadManagerShared.class getAntiAffinityNamespaceOwnedBrokers method, exclude the given namespace count add.
2. changed shouldAntiAffinityNamespaceUnload check;
3. add some unit test.

Documentation

• doc-not-needed

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