test,benchmark: enable minimal CI for http bench

[Trott]

Enable minimal CI testing for http benchmarks. This required making the
duration of some benchmarks configurable. They had been defaulting to 10
seconds each.

Checklist

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

Affected core subsystem(s)

test benchmark

[Trott]

Time to find out if this works cross-platform....

CI: https://ci.nodejs.org/job/node-test-pull-request/7025/

[Trott]

Looks like this will need one of:

• autocannon or wrk installed on all the CI machines
• configure the test to skip test files that use the external http benchmarkers (easy, but also kind of defeats the purpose of the test)
• implement a feature that allows some kind of dummy/minimal benchmarker to be used; it doesn't have to give reliable results; it just has to check the config options it receives, make sure the URL supplied is reachable, and return quickly to keep the test nice and short

The last option is probably the best? ¯\(ツ)/¯

Marking as stalled for now.

/cc @nodejs/build and @nodejs/testing in case there are any strong opinions

[Trott]

Superseded by #12121