Another go at fixing the failing sockets test

[gvilums]

What does this PR do?

Changes the leak test in socket.test.ts to establish connections sequentially instead of in parallel, ensuring it doesn't run into connection limits.

How did you verify your code works?

I'm waiting for CI to see if it's fixed

[github-actions]

❌ @gvilums, your commit has failing tests :(

💪 1 failing tests Darwin AARCH64

• test/js/node/tls/node-tls-context.test.ts 1 failing

💻 2 failing tests Darwin x64

• test/cli/install/bun-create.test.ts 2 failing
• test/cli/install/registry/bun-install-registry.test.ts 3 failing

🪟💻 7 failing tests Windows x64 baseline

• test/cli/install/bunx.test.ts 1 failing
• test/cli/install/registry/bun-install-registry.test.ts 1 failing
• test/js/bun/shell/bunshell.test.ts 1 failing
• test/js/node/dns/node-dns.test.js 2 failing
• test/js/node/http/node-http.test.ts 1 failing
• test/js/node/process/process.test.js 2 failing
• test/js/node/watch/fs.watchFile.test.ts SIGKILL

🪟💻 13 failing tests Windows x64

• test/cli/install/bunx.test.ts 1 failing
• test/cli/install/migration/migrate.test.ts 1 failing
• test/cli/install/registry/bun-install-registry.test.ts 2 failing
• test/integration/esbuild/esbuild.test.ts 1 failing
• test/integration/next-pages/test/dev-server-ssr-100.test.ts 1 failing
• test/integration/next-pages/test/dev-server.test.ts 1 failing
• test/integration/next-pages/test/next-build.test.ts 1 failing
• test/js/bun/shell/bunshell.test.ts 1 failing
• test/js/node/dns/node-dns.test.js 2 failing
• test/js/node/http/node-http.test.ts 1 failing
• test/js/node/process/process.test.js 2 failing
• test/js/node/watch/fs.watchFile.test.ts 3 failing
• test/js/web/fetch/fetch.tls.test.ts 1 failing

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