Updated xz to 5.8.1

[radarhere]

xz 5.8.1 has been released - https://github.com/tukaani-project/xz/releases/tag/v5.8.1

This updates it, except for on 32-bit Windows. That would fail with https://github.com/radarhere/Pillow/actions/runs/14264115010/job/39981991680#step:30:1096

E OSError: decoder error -2

C:\hostedtoolcache\windows\Python\3.9.13\x86\lib\site-packages\PIL\TiffImagePlugin.py:1416: OSError
---------------------------- Captured stderr call -----------------------------
LZMADecode: Decoding error at scanline 0, data is corrupt.
LZMADecode: Not enough data at scanline 0 (short 49152 bytes).

I initially reported this to libtiff at https://gitlab.com/libtiff/libtiff/-/issues/677, but have since moved on and reported it directly to xz at tukaani-project/xz#171

[radarhere]

tukaani-project/xz#171 found a workaround! I've pushed a commit to add -DXZ_CLMUL_CRC:BOOL=OFF.

[radarhere]

For anyone who is wondering, we should not be affected by https://www.cve.org/CVERecord?id=CVE-2025-31115, as libtiff uses lzma_stream_decoder, not lzma_stream_decoder_mt. See https://gitlab.com/libtiff/libtiff/-/blob/master/libtiff/tif_lzma.c