async_hooks,test: Only use IPv6 in http test

[AndreasMadsen]

If IPv6 is not supported on a machine, the IPv6 handle will first be
created, this will then fail and default to an IPv4 handle. This causes
the graph to change, as there now is an extra handle.

Fix: #18003 (comment)

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)

async_hooks

[AndreasMadsen]

CI: https://ci.nodejs.org/job/node-test-pull-request/12524/

[AndreasMadsen]

Test failure is unrelated:

sequential/test-timers-setInterval-excludes-callback-duration

assert.js:45
throw new errors.AssertionError(obj);
^
AssertionError [ERR_ASSERTION]: false == true
at Timeout.setInterval [as _onTimeout] (/home/iojs/build/workspace/node-test-binary-arm/test/sequential/test-timers-setInterval-excludes-callback-duration.js:15:5)
at ontimeout (timers.js:455:11)
at tryOnTimeout (timers.js:304:5)
at Timer.listOnTimeout (timers.js:267:5)

[AndreasMadsen]

/cc @Trott@jasnell

[Trott]

LGTM. +1 to fast-tracking.

[Trott]

Might another possibility (future enhancement, doesn't have to happen now or even ever) be to expect a different call graph in that condition rather than skipping the test?

[apapirovski]

Landed in b12425d