Skip test_highly_nested_objects_decoding during the PGO profile task.

[gpshead]

One line change to disable test_json.test_highly_nested_objects_decoding during PGO training.

Since the recursion guard tracks real C-stack bounds (gh-91079), this test asserts that 500k nesting levels overflow the stack margin. On a 64 MiB stack (some Nix build envs use one that large), the optimized interpreter uses ~160 bytes/level (raises at ~420k levels) so the assertion holds with only ~16% margin; the PGO instrumented stage inlines less, its per-level scanner frames are smaller, and the 500k-deep decode completes -- "RecursionError not raised" fails the profile run and aborts make profile-opt. Upstream's skip_if_unlimited_stack_size (gh-143460) only covers RLIM_INFINITY, not large-finite stacks like ours.

We could also keep playing whack a mole and raise the 500k to a much larger number... but there's little value in PGO training on this test anyways.

[miss-islington-app]

Thanks @gpshead for the PR 🌮🎉.. I'm working now to backport this PR to: 3.14, 3.15.
🐍🍒⛏🤖

[bedevere-app]

GH-151468 is a backport of this pull request to the 3.15 branch.

[bedevere-app]

GH-151469 is a backport of this pull request to the 3.14 branch.

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot s390x Fedora Stable Refleaks 3.14 (tier-3) has failed when building commit f892d79.

What do you need to do:

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4. Check if the failure is related to this commit (f892d79) or if it is a false positive.
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Note: switching to 'f892d79013a1f0eb00a67b902d317ef3f9e5f4d3'.

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Turn off this advice by setting config variable advice.detachedHead to false

HEAD is now at f892d79013a1f [3.14] Skip test_highly_nested_objects_decoding during the PGO profile task. (GH-151460) (#151469)
Switched to and reset branch '3.14'

ar: libpython3.14d.a: error reading Modules/posixmodule.o: No space left on device
make: *** [Makefile:1177: libpython3.14d.a] Error 1