test: fix 'localhost' ipv4 vs. ipv6 test failures in GH actions TAV tests

[trentm]

A number of TAV tests started failing in GH Actions recently, starting on Jun 12, 2024 (see x's at https://github.com/elastic/apm-agent-nodejs/commits/main/).

For example https://github.com/elastic/apm-agent-nodejs/actions/runs/9503644674

The failures were all of this basic form:

 node_tests-1  | -- running test "node test/instrumentation/modules/hapi/hapi.test.js" with @hapi/hapi (env: {})
node_tests-1  | node:events:497
node_tests-1  |       throw er; // Unhandled 'error' event
node_tests-1  |       ^
node_tests-1  | 
node_tests-1  | Error: connect ECONNREFUSED 127.0.0.1:33547
node_tests-1  |     at TCPConnectWrap.afterConnect [as oncomplete] (node:net:1606:16)
node_tests-1  | Emitted 'error' event on ClientRequest instance at:
node_tests-1  |     at Socket.socketErrorListener (node:_http_client:500:9)
node_tests-1  |     at Socket.emit (node:events:519:28)
node_tests-1  |     at emitErrorNT (node:internal/streams/destroy:169:8)
node_tests-1  |     at emitErrorCloseNT (node:internal/streams/destroy:128:3)
node_tests-1  |     at process.processTicksAndRejections (node:internal/process/task_queues:82:21) {
node_tests-1  |   errno: -111,
node_tests-1  |   code: 'ECONNREFUSED',
node_tests-1  |   syscall: 'connect',
node_tests-1  |   address: '127.0.0.1',
node_tests-1  |   port: 33547
node_tests-1  | }

• running some test (on node 18, 20, or 22)
• start some HTTP server
• error Error: connect ECONNREFUSED 127.0.0.1:${someport}

The tests were not failing locally for me on my dev macOS.
My guess is that this is about ambiguity over whether localhost is IPv4 (127.0.0.1) or IPv6 (::1).

[trentm]

/test tav @opentelemetry/api

[trentm]

/test tav @opentelemetry/api

[trentm]

/test tav @opentelemetry/api,next,@hapi/hapi