arrow

GH-43559: [Python][CI] Add a Crossbow job with a debug CPython interpreter (#43565)

### Rationale for this change

Debug builds of CPython help catch low-level errors when using the Python C API. This is illustrated in GH-43487: a debug build of CPython detected that we were incref'ing a Python object without holding the GIL (which is a race condition otherwise).

### What changes are included in this PR?

1. Add a Docker build with a conda-installed debug interpreter.
2. Add a Crossbow job to run said Docker build with Python 3.12.

### Are these changes tested?

Yes, by the adding Crossbow job. The job now fails with a crash in `test_udf.py`, because of GH-43487.

### Are there any user-facing changes?

No.
* GitHub Issue: #43559

Authored-by: Antoine Pitrou <antoine@python.org>
Signed-off-by: Antoine Pitrou <antoine@python.org>