* Unskip multiprocessing RLock repr test
Assisted-by: Grok:4.6
* Drop stable modules from the flaky MP CI list
Assisted-by: Grok:4.6
* Keep only multiprocessing fork on the flaky MP list
Assisted-by: Grok:4.6
* Drop gc_collect bench and unbreak two CI jobs
Remove benches/benchmarks/gc_collect.py so CodSpeed no longer
includes that execution benchmark.
On Windows, run test_multiprocessing_spawn serially; the
parallel snippets job hit a regrtest worker temp-dir error
while that suite was still running.
Install cargo-shear from a pinned prebuilt binary so the job
does not fall back to compiling 1.13.4 from source.
Assisted-by: Grok:4.6
* Unskip hang tests that now pass under -m test
Drop the RustPython hang skips on interpreter shutdown,
submit-after-shutdown, and connection pickling after they
passed with rustpython -m test.
Remove the unused expectedFailureIf around killpg on the
resource tracker deadlock test; os.killpg is present.
Pass matrix flaky-MP extras through the job environment
instead of interpolating them into the run script.
Assisted-by: Grok:4.6
* Restore hang skips and isolate spawn on CI
Put test_multiprocessing_spawn and
test_multiprocessing_forkserver back on the serial flaky MP
list. Ubuntu timed out in spawn test_notify_all under -j, and
forkserver.test_processes needed a rerun.
Restore the hang skips on interpreter shutdown, submit-after
shutdown, and connection pickling.
Assisted-by: Grok:4.6
Add dependency-free CPU-bound workloads adapted from pyperformance 1.14.0 to cover interpreter, standard-library serialization, regex, numeric, and garbage-collection paths under the existing Criterion and CodSpeed harnesses. Keep inputs deterministic and scale expensive cases for simulation while checking that benchmark execution does not leak interpreter state.
Assisted-by: Codex:gpt-5.6-sol