test,benchmark: stabilize child-process

[refack]

also some cleanup

Ref: #12817

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

[refack]

Stress: https://ci.nodejs.org/job/node-stress-single-test/1274/nodes=win2012r2/

[tniessen]

Just a suggestion, feel free to ignore: I would replace arguments with command lines as Windows does not really have a concept of arguments. You could even be more specific, Windows does not support command lines longer than 8191 characters (there is no reason to believe that Microsoft is going to raise that limit).

[tniessen]

This try should get rid of this error, right?

[refack]

Yep, just wrote #13457 (comment)

[refack]

@nodejs/platform-windows @gireeshpunathil help me think about this
The offending code was introduced in anchnk@ec83210

Today in https://ci.nodejs.org/job/node-test-binary-windows/8986/RUN_SUBSET=2,VS_VERSION=vs2015,label=win2012r2/console I got:

not ok 370 sequential/test-benchmark-child-process
  ---
  duration_ms: 0.623
  severity: fail
  stack: |-
    
    child_process\child-process-exec-stdout.js
    child_process\child-process-exec-stdout.js dur=0 len=1: 0
    ERROR: The process with PID 3816 (child process of PID 3692) could not be terminated.
    Reason: There is no running instance of the task.
    child_process.js:611
        throw err;
        ^
    
    Error: Command failed: taskkill /f /t /pid 3816
    ERROR: The process with PID 3816 (child process of PID 3692) could not be terminated.
    Reason: There is no running instance of the task.
    
    
        at checkExecSyncError (child_process.js:568:13)
        at Object.execSync (child_process.js:608:13)
        at Timeout._onTimeout (c:\workspace\node-test-binary-windows\RUN_SUBSET\2\VS_VERSION\vs2015\label\win2012r2\benchmark\child_process\child-process-exec-stdout.js:36:21)
        at ontimeout (timers.js:488:11)
        at tryOnTimeout (timers.js:323:5)
        at Timer.listOnTimeout (timers.js:283:5)
    assert.js:60
      throw new errors.AssertionError({
      ^
    
    AssertionError [ERR_ASSERTION]: 1 === 0
        at ChildProcess.child.on (c:\workspace\node-test-binary-windows\RUN_SUBSET\2\VS_VERSION\vs2015\label\win2012r2\test\sequential\test-benchmark-child-process.js:19:10)
        at emitTwo (events.js:125:13)
        at ChildProcess.emit (events.js:213:7)
        at Process.ChildProcess._handle.onexit (internal/child_process.js:197:12)
  ...

[refack]

Kill stress after 1000 good iterations. I call "stable".

[refack]

Prepare for landing: https://ci.nodejs.org/job/node-test-pull-request/8524/

[refack]

Landed in 8d2bd5f

[refack]

Extra sanity of master: https://ci.nodejs.org/job/node-test-commit-linuxone/6463/

[MylesBorins]

This does not land cleanly in LTS. Please feel free to manually backport. Please also feel free to replace do-not-land if it is being backported