Investigate flaky test-child-process-execFile #25029

ot ok 217 parallel/test-child-process-execfile
  ---
  duration_ms: 4.640
  severity: fail
  exitcode: 1
  stack: |-
    assert.js:86
      throw new AssertionError(obj);
      ^
    
    AssertionError [ERR_ASSERTION]: Expected values to be strictly equal:
    
    null !== 42
    
        at common.mustCall (/home/iojs/build/workspace/node-test-commit-aix/nodes/aix61-ppc64/test/parallel/test-child-process-execfile.js:20:14)
        at /home/iojs/build/workspace/node-test-commit-aix/nodes/aix61-ppc64/test/common/index.js:335:15
        at ChildProcess.exithandler (child_process.js:301:5)
        at ChildProcess.emit (events.js:189:13)
        at maybeClose (internal/child_process.js:978:16)
        at Process.ChildProcess._handle.onexit (internal/child_process.js:265:5)
  ...