Print scheduler call stack when SIGUSR2 received

[Jeffrharr]

closes: #47084

logs the stacktrace for each thread of the SchedulerJobRunner when SIGUSR2 signal is recieved.

Note for reviewers:
I set the stacktrace limit to 10, but we can increase that bound or make it a parameter in the class.

Example output - from unit test without mocks:

----------------------------------------------- Captured log call ------------------------------------------------
INFO     airflow.jobs.scheduler_job_runner.SchedulerJobRunner:scheduler_job_runner.py:260 --------------------------------------------------------------------------------
SIGHUP received, printing debug
--------------------------------------------------------------------------------
INFO     airflow.jobs.scheduler_job_runner.SchedulerJobRunner:scheduler_job_runner.py:263 Debug dump for the executor <MagicMock name='DefaultExecutor' id='140021473292144'>
INFO     airflow.jobs.scheduler_job_runner.SchedulerJobRunner:scheduler_job_runner.py:265 --------------------------------------------------------------------------------
INFO     airflow.jobs.scheduler_job_runner.SchedulerJobRunner:scheduler_job_runner.py:268 Debug dump for the executor <MagicMock name='DefaultExecutor' id='140021473292144'>
INFO     airflow.jobs.scheduler_job_runner.SchedulerJobRunner:scheduler_job_runner.py:270 --------------------------------------------------------------------------------
INFO     airflow.jobs.scheduler_job_runner.SchedulerJobRunner:scheduler_job_runner.py:263 Debug dump for the executor <MagicMock name='SeconadaryExecutor' id='140021472362016'>
INFO     airflow.jobs.scheduler_job_runner.SchedulerJobRunner:scheduler_job_runner.py:265 --------------------------------------------------------------------------------
INFO     airflow.jobs.scheduler_job_runner.SchedulerJobRunner:scheduler_job_runner.py:268 Debug dump for the executor <MagicMock name='SeconadaryExecutor' id='140021472362016'>
INFO     airflow.jobs.scheduler_job_runner.SchedulerJobRunner:scheduler_job_runner.py:270 --------------------------------------------------------------------------------
INFO     airflow.jobs.scheduler_job_runner.SchedulerJobRunner:scheduler_job_runner.py:275 Stack Trace for Scheduler Job Runner on thread: Thread-1
INFO     airflow.jobs.scheduler_job_runner.SchedulerJobRunner:scheduler_job_runner.py:277 <FrameSummary file /usr/local/lib/python3.9/threading.py, line 937 in _bootstrap>
        <FrameSummary file /usr/local/lib/python3.9/threading.py, line 980 in _bootstrap_inner>
        <FrameSummary file /usr/local/lib/python3.9/threading.py, line 917 in run>
        <FrameSummary file /usr/local/lib/python3.9/site-packages/pytest_rerunfailures.py, line 440 in run_server>
        <FrameSummary file /usr/local/lib/python3.9/socket.py, line 293 in accept>
INFO     airflow.jobs.scheduler_job_runner.SchedulerJobRunner:scheduler_job_runner.py:278 --------------------------------------------------------------------------------
INFO     airflow.jobs.scheduler_job_runner.SchedulerJobRunner:scheduler_job_runner.py:275 Stack Trace for Scheduler Job Runner on thread: MainThread
INFO     airflow.jobs.scheduler_job_runner.SchedulerJobRunner:scheduler_job_runner.py:277 <FrameSummary file /usr/local/lib/python3.9/site-packages/pluggy/_callers.py, line 103 in _multicall>
        <FrameSummary file /usr/local/lib/python3.9/site-packages/_pytest/runner.py, line 174 in pytest_runtest_call>
        <FrameSummary file /usr/local/lib/python3.9/site-packages/_pytest/python.py, line 1627 in runtest>
        <FrameSummary file /usr/local/lib/python3.9/site-packages/pluggy/_hooks.py, line 513 in __call__>
        <FrameSummary file /usr/local/lib/python3.9/site-packages/pluggy/_manager.py, line 120 in _hookexec>
        <FrameSummary file /usr/local/lib/python3.9/site-packages/pluggy/_callers.py, line 103 in _multicall>
        <FrameSummary file /usr/local/lib/python3.9/site-packages/_pytest/python.py, line 159 in pytest_pyfunc_call>
        <FrameSummary file /usr/local/lib/python3.9/unittest/mock.py, line 1768 in _inner>
        <FrameSummary file /opt/airflow/tests/jobs/test_scheduler_job.py, line 626 in test_executor_debug_dump>
        <FrameSummary file /opt/airflow/airflow/jobs/scheduler_job_runner.py, line 276 in _debug_dump>
INFO     airflow.jobs.scheduler_job_runner.SchedulerJobRunner:scheduler_job_runner.py:278 --------------------------------------------------------------------------------

---

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[boring-cyborg]

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[Jeffrharr]

@potiuk are you able to approve workflows?

[Jeffrharr]

@potiuk are you able to approve workflows?

Sorry, one more time. Hit update instead of merge and it has to rerun tests.

I believe those workflows should work for me after making this initial commit?

[o-nikolas]

@potiuk are you able to approve workflows?

Sorry, one more time. Hit update instead of merge and it has to rerun tests.

I believe those workflows should work for me after making this initial commit?

Approved. Yupp, once you've got your first commit merged, you should be able to approve them yourself 🥳

[boring-cyborg]

Awesome work, congrats on your first merged pull request! You are invited to check our Issue Tracker for additional contributions.