test: fix flaky test-http-server-consumed-timeout

Checklist

• make -j4 test (UNIX), or vcbuild test nosign (Windows) passes
• tests and/or benchmarks are included
• commit message follows commit guidelines

Affected core subsystem(s)

test http

Description of change

Using identical timeout values appears to have eliminated the flakiness in the test.

Fixes: https://github.com/nodejs/node/issues/7643

With this change to the test and removing the fix in https://github.com/nodejs/node/pull/6286, everything fails (as it should): https://ci.nodejs.org/job/node-stress-single-test/804/ (Test run just once on each platform)

With this change to the test only, everything passes (as it should): https://ci.nodejs.org/job/node-stress-single-test/805/ (Test run 100 times on each platform)

And with this change, the test is not flaky on FreeBSD: https://ci.nodejs.org/job/node-stress-single-test/806/nodes=freebsd10-64/console (9999 runs, 0 failures)

For comparison, the test is flaky on current master on FreeBSD: https://ci.nodejs.org/job/node-stress-single-test/807/nodes=freebsd10-64/console (also 9999 runs, 1 failure, so not the overwhelming results I was hoping for, but at least it wasn't 0 failures...)

/cc @indutny

The flakiness is not terribly reproducible in the stress tests, but if it stands to reason that this reduces any race condition window, then it's probably worth doing.