Investigate stack-8.6.5 test failure

[adinapoli]

Run stack test --system-ghc --stack-yaml stack-8.6.5.yaml
threads-supervisor> test (suite: threads-supervisor-tests)
All Tests
  Control.Concurrent.Supervisor
    1 supervised thread, no exceptions:             OK
      +++ OK, passed 20 tests.
    1 supervised thread, premature async exception: OK (22.88s)
      +++ OK, passed 20 tests.
    1 supervised thread, premature exception:       OK (25.87s)
      +++ OK, passed 20 tests.
    1 supervised supervisor, premature exception:   OK (2[4](https://github.com/adinapoli/threads-supervisor/runs/6772217875?check_suite_focus=true#step:6:5).[5](https://github.com/adinapoli/threads-supervisor/runs/6772217875?check_suite_focus=true#step:6:6)4s)
      +++ OK, passed 20 tests.
    killing spree:                                  OK ([6](https://github.com/adinapoli/threads-supervisor/runs/6772217875?check_suite_focus=true#step:6:7)[7](https://github.com/adinapoli/threads-supervisor/runs/6772217875?check_suite_focus=true#step:6:8).10s)
      +++ OK, passed 20 tests.
    cleanup:                                        OK (79.13s)
      +++ OK, passed 20 tests.
    too many restarts:                              OK (2.00s)
  Control.Concurrent.Supervisor.Bounded
    1 supervised thread, no exceptions:             OK
      +++ OK, passed 20 tests.
    1 supervised thread, premature exception:       OK (23.16s)
      +++ OK, passed 20 tests.
    killing spree:                                  OK (65.2[8](https://github.com/adinapoli/threads-supervisor/runs/6772217875?check_suite_focus=true#step:6:9)s)
      +++ OK, passed 20 tests.
    cleanup:                                        OK (7[9](https://github.com/adinapoli/threads-supervisor/runs/6772217875?check_suite_focus=true#step:6:10).18s)
      +++ OK, passed 20 tests.
    too many restarts:                              FAIL (2.00s)
      test/Tests/Bounded.hs:92:
      assertContainsNMsg: list exhausted and 1 left.
1 out of [12](https://github.com/adinapoli/threads-supervisor/runs/6772217875?check_suite_focus=true#step:6:13) tests failed ([20](https://github.com/adinapoli/threads-supervisor/runs/6772217875?check_suite_focus=true#step:6:21)5.72s)