gh-150167

Make shutil detect compression-module support eagerly even when Python starts with -X lazy_imports=all.

This keeps _BZ2_SUPPORTED accurate when bz2 imports successfully but its _bz2 backend would fail once reified. The support probe now temporarily disables lazy imports while importing the compression module, and the regression test exercises that failure mode in a subprocess.

Testing

• ./python.exe -m test test_shutil
• ./python.exe -m test test_lazy_import
• ./python.exe -X lazy_imports=all -S -c "import sys; sys.path.insert(0, TMPDIR); import shutil; print(shutil._BZ2_SUPPORTED)" (with a fake bz2 module whose _bz2 backend raises ImportError)