Update Android test-command handling (#2590)

* Update Android test-command handling

* Update to Python 3.13.8

* Update documentation and tests

* Deal with `sysconfig.get_config_var("exec_prefix")` changing in Python 3.14, and add cross venv tests

* Allow test commands starting with `python3`

* test-command cleanups

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

test/_cross_venv_test_android.py

@@ -0,0 +1,20 @@
+import sys
+import sysconfig
+from pathlib import Path
+
+assert sys.platform == "android"
+assert sysconfig.get_platform().startswith("android-")
+
+android_prefix = Path(f"{sys.prefix}/../python/prefix").resolve()
+assert android_prefix.is_dir()
+
+vars = sysconfig.get_config_vars()
+assert vars["INCLUDEDIR"] == f"{android_prefix}/include"
+assert vars["LDVERSION"] == f"{sys.version_info[0]}.{sys.version_info[1]}{sys.abiflags}"
+assert vars["INCLUDEPY"] == f"{vars['INCLUDEDIR']}/python{vars['LDVERSION']}"
+assert vars["LIBDIR"] == f"{android_prefix}/lib"
+assert vars["Py_ENABLE_SHARED"] == 1
+
+paths = sysconfig.get_paths()
+assert paths["include"] == vars["INCLUDEPY"]
+assert paths["platinclude"] == vars["INCLUDEPY"]