test: deflake util.throttle tests

[panva]

Short throttle windows can expire between synchronous calls when the process is descheduled. Delayed timer dispatch can also release two queued calls together, invalidating the strict test's spacing assertion.

Move timing checks to a separate test with mocked timers and a matching libuv clock. Cover both punctual and delayed dispatch, and keep real async_hooks timer-allocation checks with windows canceled before expiry.

Refs: #65899
Refs: https://ci.nodejs.org/job/node-test-commit-linux-containered/nodes=ubuntu2404_sharedlibs_openssl111_x64/59189/
Refs: https://ci.nodejs.org/job/node-test-commit-linuxone/nodes=rhel8-s390x/58602/

Assisted-by: Codex

---
duration_ms: 399.938
exitcode: 1
severity: fail
stack: |-
  node:assert:173
    throw err;
    ^

  AssertionError [ERR_ASSERTION]: function should not have been called at /home/iojs/build/workspace/node-test-commit-linuxone/test/parallel/test-util-throttle.js:11
  called with arguments: AssertionError [ERR_ASSERTION]: The expression evaluated to a falsy value:

    assert(times[3] - times[2] >= 25)

      at /home/iojs/build/workspace/node-test-commit-linuxone/test/parallel/test-util-throttle.js:293:5 {
    generatedMessage: true,
    code: 'ERR_ASSERTION',
    actual: false,
    expected: true,
    operator: '==',
    diff: 'simple'
  }, Promise {
    <rejected> AssertionError [ERR_ASSERTION]: The expression evaluated to a falsy value:

      assert(times[3] - times[2] >= 25)

        at /home/iojs/build/workspace/node-test-commit-linuxone/test/parallel/test-util-throttle.js:293:5 {
      generatedMessage: true,
      code: 'ERR_ASSERTION',
      actual: false,
      expected: true,
      operator: '==',
      diff: 'simple'
    }
  }
      at process.mustNotCall (/home/iojs/build/workspace/node-test-commit-linuxone/test/common/index.js:570:12)
      at process.emit (node:events:514:20)
      at emitUnhandledRejection (node:internal/process/promises:182:13)
      at throwUnhandledRejectionsMode (node:internal/process/promises:318:19)
      at processPromiseRejections (node:internal/process/promises:405:17)
      at process.processTicksAndRejections (node:internal/process/task_queues:106:37) {
    generatedMessage: false,
    code: 'ERR_ASSERTION',
    actual: undefined,
    expected: undefined,
    operator: 'fail',
    diff: 'simple'
  }

  Node.js v27.0.0-pre
...

[github-actions]

Fast-track has been requested by @panva. Please 👍 to approve.

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/77512/

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.22%. Comparing base (26dbe11) to head (ed130fc).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #66034      +/-   ##
==========================================
- Coverage   90.23%   90.22%   -0.02%     
==========================================
  Files         789      789              
  Lines      270415   270476      +61     
  Branches    51756    51740      -16     
==========================================
+ Hits       244018   244027       +9     
- Misses      16868    16921      +53     
+ Partials     9529     9528       -1     

see 28 files with indirect coverage changes

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[mcollina]

lgtm

[aduh95]

Suggested change

	})().then(common.mustCall()).finally(() => mock.reset());
	})().finally(() => mock.reset()).then(common.mustCall());

[nodejs-github-bot]

Landed in 84e9174