Fix HTTP client load balancing for multi-homed hosts

[arnabnandy7]

Motivation:

An HttpClient configured with a LoadBalancer resolved every address for a multi-homed host, but requests still connected to only one IP.

The resolved InetAddress instances retained the original hostname. As a result, the generated SocketAddress instances compared equally and shared the same connection-pool key, despite representing different IP addresses.

This change creates socket addresses using the resolved numeric IP while retaining the original InetAddress. Each resolved IP therefore receives a distinct connection pool and can be selected by the configured load balancer.

The existing DNS client-side load-balancing test now also verifies that DNS results produce distinct server addresses.

Fixes #6200

Conformance:

I have signed the Eclipse Contributor Agreement as explained in https://github.com/eclipse/vert.x/blob/master/CONTRIBUTING.md

I have followed the Vert.x code style guidelines: https://github.com/vert-x3/wiki/wiki/Vert.x-code-style-guidelines

Verification:

mvn -pl vertx-core -Dtest=Http1xTest#testDnsClientSideLoadBalancingEnabled test

Tests run: 1, Failures: 0, Errors: 0, Skipped: 0