ci-test-gc-core failed: A "spawn and wait lots of tasks" test failed

[qinsoon]

In https://github.com/mmtk/mmtk-core/actions/runs/7603829506/job/20706033725?pr=1073, there is a random failure in the threads tests.

threads
-> Run
Whitespace check found no issues.
    JULIA test/threads
Running parallel tests with:
  nworkers() = 1
  nthreads() = 4
  Sys.CPU_THREADS = 2
  Sys.total_memory() = 15.607 GiB
  Sys.free_memory() = 14.190 GiB

Test  (Worker) | Time (s) | GC (s) | GC % | Alloc (MB) | RSS (MB)
threads    (1) |        started at 2024-01-21T21:25:57.844
Test Summary:                               |  Pass  Total   Time
threads_exec.jl with JULIA_NUM_THREADS == 1 | 40353  40353  37.4s
Test Summary:                               |  Pass  Total   Time
threads_exec.jl with JULIA_NUM_THREADS == 2 | 45713  45713  34.6s
Test Summary:                               |  Pass  Total   Time
threads_exec.jl with JULIA_NUM_THREADS == 4 | 43803  43803  35.1s
Test Summary:                               |  Pass  Total   Time
threads_exec.jl with JULIA_NUM_THREADS == 4 | 47103  47103  35.6s
┌ Error: A "spawn and wait lots of tasks" test failed
│   n = 2000000
│   proc.exitcode = 0
│   proc.termsignal = 0
│   success(proc) = true
│   timeout = true
└ @ Main.Test84Main_threads ~/work/mmtk-core/mmtk-core/mmtk-julia/vm/julia/test/threads.jl:313
threads    (1) |         failed at 2024-01-21T21:30:56.635
Test Failed at /home/runner/work/mmtk-core/mmtk-core/mmtk-julia/vm/julia/test/threads.jl:320
  Expression: !timeout



Test Summary: | Pass  Fail  Total  Time
  Overall     |   50     1     51  0.5s
    threads   |   50     1     51  4m59.5s
    FAILURE

The global RNG seed was 0x7cd3376b3527438d6fed6c7518c967bd.

Error in testset threads:
Test Failed at /home/runner/work/mmtk-core/mmtk-core/mmtk-julia/vm/julia/test/threads.jl:320
  Expression: !timeout

ERROR: LoadError: Test run finished with errors
in expression starting at /home/runner/work/mmtk-core/mmtk-core/mmtk-julia/vm/julia/test/runtests.jl:95
make[1]: *** [Makefile:30: threads] Error 1
make: *** [Makefile:633: test-threads] Error 2

[udesou]

Note that it failed on Mac and windows for stock Julia, so I'm not sure if this is mmtk-specific: JuliaLang/julia#43124 (comment)