test: reduce test-hash-seed run time by half

[Trott]

Reduce the time it takes to run test/pummel/test-hash-seed by switching
from spawnSync() to spawn(). On my computer, this reduces the runtime
from about 80 seconds to about 40 seconds. This test is not (yet) run
regularly on CI, but when it was run recently, it timed out.

While we're in there, replace min() function with Math.min(...). It's in a separate commit because it's unrelated, but I couldn't bring myself to not do it at all.

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

[nodejs-github-bot]

@Trott build started: https://ci.nodejs.org/blue/organizations/jenkins/node-test-pull-request-lite-pipeline/detail/node-test-pull-request-lite-pipeline/2256/pipeline

[Trott]

(By the way, does anyone know if this test is even valid anymore? I imagine it is, but I don't know where the hash-seed is calculated. It looks like the fixture maybe copies some code from someplace else and therefore might theoretically be out of date? @ofrobots @nodejs/v8 )

[Trott]

Lite CI should be sufficient because pummel tests aren't yet run in CI. Here's a custom run to exercise just this test to confirm that it won't time out anymore (or at least won't always time out) in CI: https://ci.nodejs.org/job/node-test-commit-custom-suites-freestyle/3908/

[ofrobots]

@Trott

(By the way, does anyone know if this test is even valid anymore? I imagine it is, but I don't know where the hash-seed is calculated. It looks like the fixture maybe copies some code from someplace else and therefore might theoretically be out of date?

Yes, the test is still relevant. This ensures that we are building V8 in a way to make sure the V8's internal hash seed is not predictable. See CVE-2017-11499. This is not an important attack vector for browsers, so this kind of stuff is likely going to be configuration flag for V8 going forward. The test ensures that we are setting the flag correct and V8 itself is not regressing.

[refack]

By the way, does anyone know if this test is even valid anymore?

IIUC this could be tested with node8 < v8.1.4

reduce test-hash-seed run time by half

[nit] Only on multi-core/hyper-threaded machines. For example our Windows 10 CI machines are single core.

[Trott]

Lite CI: https://ci.nodejs.org/job/node-test-pull-request-lite-pipeline/2260/

Running the test on CI (scheduled): https://ci.nodejs.org/job/node-test-commit-custom-suites-freestyle/3915/

[refack]

Test still works (after a bit of massage to common/index.js)

DEV D:\code\prws>node8.1.3 test\pummel\test-hash-seed.js
Seeds: 60421████,60421████
assert.js:60
  throw new errors.AssertionError({
  ^

AssertionError [ERR_ASSERTION]: 1 === 2
    at Countdown.requiredCallback (D:\code\prws\test\pummel\test-hash-seed.js:15:10)
    at Countdown.<anonymous> (D:\code\prws\test\common\index.js:378:15)
    at Countdown.dec (D:\code\prws\test\common\countdown.js:21:22)
    at ChildProcess.subprocess.on (D:\code\prws\test\pummel\test-hash-seed.js:29:15)
    at emitTwo (events.js:125:13)
    at ChildProcess.emit (events.js:213:7)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:197:12)

DEV D:\code\prws>node8.1.4 test\pummel\test-hash-seed.js
Seeds: 802238064,671715787

[Trott]

Landed in 5fdd554...f2e3a4e