A host can't connect and won't try other hosts again in multi-hosts service url configuration

**Describe the bug**

Use "pulsar://host1:6650,host2:6650,127.0.0.1:6650" as service url to create a pulsar client, "host1" and "host2" is the wrong hosts, not every time I can successfully connect to "127.0.0.1:6650".

**To Reproduce**
```
public void testRetryWithMultiHostServiceUrl() throws PulsarClientException {
String serviceUrl = "pulsar://host1:6650,host2:6650,127.0.0.1:" + BROKER_PORT;
PulsarClient client = PulsarClient.builder().serviceUrl(serviceUrl).build();
Producer producer = client.newProducer().topic("persistent://my-property/my-ns/multi-host").create();
assertNotNull(producer);
}
```
Sometimes will get "java.net.UnknownHostException" and sometimes will connect success.
Here is the stack trace while create producer failed:
```
org.apache.pulsar.client.api.PulsarClientException: java.util.concurrent.CompletionException: java.net.UnknownHostException: failed to resolve 'host1' after 6 queries

at org.apache.pulsar.client.impl.ConnectionPool.lambda$null$9(ConnectionPool.java:202)
at io.netty.util.concurrent.AbstractEventExecutor.safeExecute$$$capture(AbstractEventExecutor.java:163)
at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java)
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:404)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:474)
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:909)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.util.concurrent.CompletionException: java.net.UnknownHostException: failed to resolve 'host1' after 6 queries
at java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:292)
at java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:308)
at java.util.concurrent.CompletableFuture.uniCompose(CompletableFuture.java:943)
at java.util.concurrent.CompletableFuture$UniCompose.tryFire(CompletableFuture.java:926)
at java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:474)
at java.util.concurrent.CompletableFuture.completeExceptionally(CompletableFuture.java:1977)
at org.apache.pulsar.client.impl.ConnectionPool.lambda$resolveName$16(ConnectionPool.java:259)
at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:511)
at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:485)
at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:424)
at io.netty.util.concurrent.DefaultPromise.tryFailure(DefaultPromise.java:121)
at io.netty.resolver.dns.DnsResolveContext.finishResolve(DnsResolveContext.java:856)
at io.netty.resolver.dns.DnsResolveContext.tryToFinishResolve(DnsResolveContext.java:809)
at io.netty.resolver.dns.DnsResolveContext.query(DnsResolveContext.java:332)
at io.netty.resolver.dns.DnsResolveContext.onResponse(DnsResolveContext.java:495)
at io.netty.resolver.dns.DnsResolveContext.access$400(DnsResolveContext.java:62)
at io.netty.resolver.dns.DnsResolveContext$3.operationComplete(DnsResolveContext.java:376)
at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:511)
at io.netty.util.concurrent.DefaultPromise.notifyListeners0(DefaultPromise.java:504)
at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:483)
at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:424)
at io.netty.util.concurrent.DefaultPromise.trySuccess(DefaultPromise.java:103)
at io.netty.resolver.dns.DnsQueryContext.setSuccess(DnsQueryContext.java:196)
at io.netty.resolver.dns.DnsQueryContext.finish(DnsQueryContext.java:188)
at io.netty.resolver.dns.DnsNameResolver$DnsResponseHandler.channelRead(DnsNameResolver.java:1149)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1434)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:965)
at io.netty.channel.nio.AbstractNioMessageChannel$NioMessageUnsafe.read(AbstractNioMessageChannel.java:93)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:656)
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:591)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:508)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:470)
... 3 more
Caused by: java.net.UnknownHostException: failed to resolve 'host1' after 6 queries
at io.netty.resolver.dns.DnsResolveContext.finishResolve(DnsResolveContext.java:848)
... 32 more

```
**Expected behavior**

Pulsar client should try to connect to each hosts, only all the hosts can't connect successfully return the error message to users.

Start with ConnectionPool.java, especially the failure paths around lines 202 and 259, and run the provided testRetryWithMultiHostServiceUrl reproduction. Trace how failures for host1 and host2 affect attempts to reach 127.0.0.1. Done means the client tries each configured host and reports an error only when all hosts fail.

Written by the indexing model from the issue text.