Investigate root cause for quarantined test RackAwareTest.testPlacement since it might be a real production code issue

**Describe the bug**

Flaky test RackawareTest.testPlacement has been moved to quarantine test group so that it doesn't block CI, this change was made in #11370.

The root cause seems to be a production code issue. The stacktrace shown in the logs of a failing test hints that there might be a dead lock that happens. One common issue is locking up Zookeeper threads when Zookeeper operations are initiated from a zookeeper thread that notifies about a change (example of such issue is #10418).

```
12:15:18.019 [ForkJoinPool.commonPool-worker-1] WARN org.apache.pulsar.zookeeper.ZooKeeperDataCache - Reloading ZooKeeperDataCache failed at path: /bookies
java.util.concurrent.CompletionException: java.lang.RuntimeException: java.util.concurrent.TimeoutException
at java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:314) ~[?:?]
at java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:319) ~[?:?]
at java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:718) ~[?:?]
at java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:506) ~[?:?]
at java.util.concurrent.CompletableFuture.complete(CompletableFuture.java:2073) ~[?:?]
at org.apache.pulsar.zookeeper.ZooKeeperCache.lambda$getDataAsync$17(ZooKeeperCache.java:386) ~[pulsar-zookeeper-utils-2.9.0-SNAPSHOT.jar:2.9.0-SNAPSHOT]
at java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:714) ~[?:?]
at java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:506) ~[?:?]
at java.util.concurrent.CompletableFuture.complete(CompletableFuture.java:2073) ~[?:?]
at org.apache.pulsar.zookeeper.ZooKeeperCache.lambda$getDataAsync$11(ZooKeeperCache.java:366) ~[pulsar-zookeeper-utils-2.9.0-SNAPSHOT.jar:2.9.0-SNAPSHOT]
at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1426) [?:?]
at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:290) [?:?]
at java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1020) [?:?]
at java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1656) [?:?]
at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1594) [?:?]
at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:183) [?:?]
Caused by: java.lang.RuntimeException: java.util.concurrent.TimeoutException
at org.apache.pulsar.zookeeper.ZkBookieRackAffinityMapping.getRack(ZkBookieRackAffinityMapping.java:195) ~[pulsar-zookeeper-utils-2.9.0-SNAPSHOT.jar:2.9.0-SNAPSHOT]
at org.apache.pulsar.zookeeper.ZkBookieRackAffinityMapping.resolve(ZkBookieRackAffinityMapping.java:179) ~[pulsar-zookeeper-utils-2.9.0-SNAPSHOT.jar:2.9.0-SNAPSHOT]
at org.apache.bookkeeper.client.TopologyAwareEnsemblePlacementPolicy$DNSResolverDecorator.resolve(TopologyAwareEnsemblePlacementPolicy.java:561) ~[bookkeeper-server-4.14.1.jar:4.14.1]
at org.apache.bookkeeper.net.NetUtils.resolveNetworkLocation(NetUtils.java:88) ~[bookkeeper-server-4.14.1.jar:4.14.1]
at org.apache.bookkeeper.client.TopologyAwareEnsemblePlacementPolicy.resolveNetworkLocation(TopologyAwareEnsemblePlacementPolicy.java:794) ~[bookkeeper-server-4.14.1.jar:4.14.1]
at org.apache.bookkeeper.client.TopologyAwareEnsemblePlacementPolicy.createBookieNode(TopologyAwareEnsemblePlacementPolicy.java:784) ~[bookkeeper-server-4.14.1.jar:4.14.1]
at org.apache.bookkeeper.client.TopologyAwareEnsemblePlacementPolicy.onBookieRackChange(TopologyAwareEnsemblePlacementPolicy.java:747) ~[bookkeeper-server-4.14.1.jar:4.14.1]
at org.apache.bookkeeper.client.RackawareEnsemblePlacementPolicyImpl.onBookieRackChange(RackawareEnsemblePlacementPolicyImpl.java:80) ~[bookkeeper-server-4.14.1.jar:4.14.1]
at org.apache.pulsar.zookeeper.ZkBookieRackAffinityMapping.onUpdate(ZkBookieRackAffinityMapping.java:242) ~[pulsar-zookeeper-utils-2.9.0-SNAPSHOT.jar:2.9.0-SNAPSHOT]
at org.apache.pulsar.zookeeper.ZkBookieRackAffinityMapping.onUpdate(ZkBookieRackAffinityMapping.java:53) ~[pulsar-zookeeper-utils-2.9.0-SNAPSHOT.jar:2.9.0-SNAPSHOT]
at org.apache.pulsar.zookeeper.ZooKeeperDataCache.lambda$reloadCache$3(ZooKeeperDataCache.java:138) ~[pulsar-zookeeper-utils-2.9.0-SNAPSHOT.jar:2.9.0-SNAPSHOT]
at java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:714) ~[?:?]
... 13 more
Caused by: java.util.concurrent.TimeoutException
at java.util.concurrent.CompletableFuture.timedGet(CompletableFuture.java:1886) ~[?:?]
at java.util.concurrent.CompletableFuture.get(CompletableFuture.java:2021) ~[?:?]
at org.apache.pulsar.zookeeper.ZooKeeperDataCache.get(ZooKeeperDataCache.java:97) ~[pulsar-zookeeper-utils-2.9.0-SNAPSHOT.jar:2.9.0-SNAPSHOT]
at org.apache.pulsar.zookeeper.ZkBookieRackAffinityMapping.getRack(ZkBookieRackAffinityMapping.java:187) ~[pulsar-zookeeper-utils-2.9.0-SNAPSHOT.jar:2.9.0-SNAPSHOT]
at org.apache.pulsar.zookeeper.ZkBookieRackAffinityMapping.resolve(ZkBookieRackAffinityMapping.java:179) ~[pulsar-zookeeper-utils-2.9.0-SNAPSHOT.jar:2.9.0-SNAPSHOT]
at org.apache.bookkeeper.client.TopologyAwareEnsemblePlacementPolicy$DNSResolverDecorator.resolve(TopologyAwareEnsemblePlacementPolicy.java:561) ~[bookkeeper-server-4.14.1.jar:4.14.1]
at org.apache.bookkeeper.net.NetUtils.resolveNetworkLocation(NetUtils.java:88) ~[bookkeeper-server-4.14.1.jar:4.14.1]
at org.apache.bookkeeper.client.TopologyAwareEnsemblePlacementPolicy.resolveNetworkLocation(TopologyAwareEnsemblePlacementPolicy.java:794) ~[bookkeeper-server-4.14.1.jar:4.14.1]
at org.apache.bookkeeper.client.TopologyAwareEnsemblePlacementPolicy.createBookieNode(TopologyAwareEnsemblePlacementPolicy.java:784) ~[bookkeeper-server-4.14.1.jar:4.14.1]
at org.apache.bookkeeper.client.TopologyAwareEnsemblePlacementPolicy.onBookieRackChange(TopologyAwareEnsemblePlacementPolicy.java:747) ~[bookkeeper-server-4.14.1.jar:4.14.1]
at org.apache.bookkeeper.client.RackawareEnsemblePlacementPolicyImpl.onBookieRackChange(RackawareEnsemblePlacementPolicyImpl.java:80) ~[bookkeeper-server-4.14.1.jar:4.14.1]
at org.apache.pulsar.zookeeper.ZkBookieRackAffinityMapping.onUpdate(ZkBookieRackAffinityMapping.java:242) ~[pulsar-zookeeper-utils-2.9.0-SNAPSHOT.jar:2.9.0-SNAPSHOT]
at org.apache.pulsar.zookeeper.ZkBookieRackAffinityMapping.onUpdate(ZkBookieRackAffinityMapping.java:53) ~[pulsar-zookeeper-utils-2.9.0-SNAPSHOT.jar:2.9.0-SNAPSHOT]
at org.apache.pulsar.zookeeper.ZooKeeperDataCache.lambda$reloadCache$3(ZooKeeperDataCache.java:138) ~[pulsar-zookeeper-utils-2.9.0-SNAPSHOT.jar:2.9.0-SNAPSHOT]
at java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:714) ~[?:?]
... 13 more
```

Begin with RackAwareTest.testPlacement and the quarantining change in #11370, then trace the stack frames through ZooKeeperDataCache, ZkBookieRackAffinityMapping, and the rack-aware placement callbacks. Reproduce the timeout or deadlock if possible and compare with #10418. Done means the root cause is identified and the relevant production issue or test behavior is validated so the test no longer requires quarantine.

Written by the indexing model from the issue text.