[2.7] bpo-29110: Fix file object leak in aifc.open by methane · Pull Request #356 · python/cpython

Codification batch item 3 per supervisor 18:09:43Z dispatch.
Discharges queue item 8 from supervisor 14:21:53Z disposition of
pythia python#356 (3).

Documents the rule that future load-only failures of test_multiprocessing_fork
on subsequent c-series default to INTRODUCED until a load-faithful
falsifier (matching original -j8 --timeout=120 conditions) clears.
Closes the asymmetry that flake-reclassification via N-run isolation
would re-fire on every recurrence, masking real load-class regressions
(per feedback_assume_phoenix_regression).

Currently-affected: test.test_multiprocessing_fork.test_threads (first
load-fail c2 12:06Z, reclassified flake 12:27Z, next load-fail = INTRODUCED).

Pre-existing CPython + ARM64-specific stdlib failure sets remain
excluded (predate c-series, gate-script-non-blocking policy unchanged).