test: refactor test-http-destroyed-socket-write2

Remove the limit of requests to be sent (128) as in some conditions it
was reached without the `error` event being fired, causing the test to
fail.

Remove the initial timeout.

Remove some variables used to check the validity of the test and replace
them with `common.mustCall` and `common.fail` calls.

PR-URL: https://github.com/nodejs/node/pull/4970


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Roman Klauke <romaaan.git@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>