python3: update to 3.13.15

Update to the latest 3.13 bugfix release.

Bump PYTHON3_PIP_VERSION to 26.2.1 to match the pip wheel bundled in
ensurepip, which the host build checks for. This pip also fixes
CVE-2026-3219 in the host pip.

Drop 100-test_hashlib-better-handle-support-for-SHA3.patch, which is
included upstream since 3.13.10 (gh-141907).

Refresh the other patches. Only the hunk offsets changed, and the
changed patches get the git headers they have in master.

The bundled libexpat, which the target build uses, goes from 2.7.3 to
2.8.2.

Fixes CVEs:
CVE-2025-6075, CVE-2025-8291, CVE-2025-11468, CVE-2025-12084,
CVE-2025-13462, CVE-2025-13836, CVE-2025-13837, CVE-2025-15282,
CVE-2025-15366, CVE-2026-0672, CVE-2026-0864, CVE-2026-0865,
CVE-2026-1299, CVE-2026-1502, CVE-2026-2297, CVE-2026-3276,
CVE-2026-3446, CVE-2026-3644, CVE-2026-4224, CVE-2026-4360,
CVE-2026-4519, CVE-2026-4786, CVE-2026-6019, CVE-2026-6100,
CVE-2026-6879, CVE-2026-7210, CVE-2026-7774, CVE-2026-8328,
CVE-2026-9669, CVE-2026-11940, CVE-2026-11972, CVE-2026-12003,
CVE-2026-15308, CVE-2026-18503, CVE-2026-45186

Release notes:
https://docs.python.org/release/3.13.15/whatsnew/changelog.html

Signed-off-by: Josef Schlehofer <pepe.schlehofer@gmail.com>

lang/python/python3-version.mk

@@ -8,9 +8,9 @@
 # Note: keep in sync with pip
 PYTHON3_VERSION_MAJOR:=3
 PYTHON3_VERSION_MINOR:=13
-PYTHON3_VERSION_MICRO:=9
+PYTHON3_VERSION_MICRO:=15
 
 PYTHON3_VERSION:=$(PYTHON3_VERSION_MAJOR).$(PYTHON3_VERSION_MINOR)
 
 PYTHON3_PIP_PKG_RELEASE:=1
-PYTHON3_PIP_VERSION:=25.2
+PYTHON3_PIP_VERSION:=26.2.1