test_sampling_profiler: test_run_failed_script_live() failed on s390x LTO+PGO build: "Failed to find the PyRuntime section"

s390x Fedora Stable LTO + PGO 3.x: https://buildbot.python.org/#/builders/1627/builds/3165

Previous builds are fine, the error may depend on how PGO decides to optimize the code. I bet that the test will pass on the next build.

Logs:

ERROR: test_run_failed_script_live (test.test_profiling.test_sampling_profiler.test_live_collector_ui.TestLiveModeErrors.test_run_failed_script_live)
Test that running a failing script exits with clean error.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/var/lib/buildbot/worker/cstratak-fedora-stable-s390x/3.x.cstratak-fedora-stable-s390x.lto-pgo/build/Lib/profiling/sampling/sample.py", line 87, in __init__
    self.unwinder = self._new_unwinder(native, gc, opcodes, skip_non_matching_threads)
                    ~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/var/lib/buildbot/worker/cstratak-fedora-stable-s390x/3.x.cstratak-fedora-stable-s390x.lto-pgo/build/Lib/profiling/sampling/sample.py", line 102, in _new_unwinder
    return _remote_debugging.RemoteUnwinder(
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        self.pid,
        ^^^^^^^^^
    ...<7 lines>...
        **kwargs
        ^^^^^^^^
    )
    ^
RuntimeError: Failed to find the PyRuntime section in process 149156 on Linux platform

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/var/lib/buildbot/worker/cstratak-fedora-stable-s390x/3.x.cstratak-fedora-stable-s390x.lto-pgo/build/Lib/test/test_profiling/test_sampling_profiler/test_live_collector_ui.py", line 900, in test_run_failed_script_live
    main()
    ~~~~^^
  File "/var/lib/buildbot/worker/cstratak-fedora-stable-s390x/3.x.cstratak-fedora-stable-s390x.lto-pgo/build/Lib/profiling/sampling/cli.py", line 989, in main
    _main()
    ~~~~~^^
  File "/var/lib/buildbot/worker/cstratak-fedora-stable-s390x/3.x.cstratak-fedora-stable-s390x.lto-pgo/build/Lib/profiling/sampling/cli.py", line 1145, in _main
    handler(args)
    ~~~~~~~^^^^^^
  File "/var/lib/buildbot/worker/cstratak-fedora-stable-s390x/3.x.cstratak-fedora-stable-s390x.lto-pgo/build/Lib/profiling/sampling/cli.py", line 1251, in _handle_run
    _handle_live_run(args)
    ~~~~~~~~~~~~~~~~^^^^^^
  File "/var/lib/buildbot/worker/cstratak-fedora-stable-s390x/3.x.cstratak-fedora-stable-s390x.lto-pgo/build/Lib/profiling/sampling/cli.py", line 1386, in _handle_live_run
    sample_live(
    ~~~~~~~~~~~^
        process.pid,
        ^^^^^^^^^^^^
    ...<9 lines>...
        blocking=args.blocking,
        ^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/var/lib/buildbot/worker/cstratak-fedora-stable-s390x/3.x.cstratak-fedora-stable-s390x.lto-pgo/build/Lib/profiling/sampling/sample.py", line 610, in sample_live
    profiler = SampleProfiler(
        pid,
    ...<8 lines>...
        blocking=blocking,
    )
  File "/var/lib/buildbot/worker/cstratak-fedora-stable-s390x/3.x.cstratak-fedora-stable-s390x.lto-pgo/build/Lib/profiling/sampling/sample.py", line 89, in __init__
    raise SystemExit(err) from err
SystemExit: Failed to find the PyRuntime section in process 149156 on Linux platform

cc @stratakis

Start by running test_run_failed_script_live() in test/test_profiling/test_sampling_profiler/test_live_collector_ui.py on the s390x Fedora Stable LTO+PGO build. Trace SampleProfiler initialization and _new_unwinder() in Lib/profiling/sampling/sample.py, using the linked build logs as context. Done means the test reliably handles the process and no longer fails with “Failed to find the PyRuntime section.”