test: reduce timeouts in test-net-keepalive
test: reduce timeouts in test-net-keepalive

Previously 1000-1200ms, they're now (platform dependent) 50-100ms.

Improves test run time on my machine from 0m1.335s to 0m0.236s.

PR-URL: https://github.com/nodejs/node/pull/2429
Reviewed-By: Rich Trott <28a7b6144c43947e3f532c033ff42c8a2ae08045@gmail.com>

dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node