textproc/py-pylibxml2: rm patch that scans garbage

Remove a local patch that scans stack garbage for a pattern and then uses
the pointer after the array has been filled with actual data.  This can
cause random segfaults.

The patch is under textproc/libxml2, but the patched file is only used by
textproc/py-pylibxml2.

The UTF-8 issue this was intended to fix was fixed upstream in a more
comprehensive way in 2.11.0 with this commit:
https://gitlab.gnome.org/GNOME/libxml2/-/commit/76c6da420923f2721a2e16adfcef8707a2454a1b

PR:		286439 279034
Approved by:	desktop (makc)
Tested by:	vvd
MFH:		2025Q2