gh-99370: Prefer LIBDIR from sysconfig when locating libpython for test (GH-99523)

(cherry picked from commit 7c57857)

Co-authored-by: Steve Dower <steve.dower@python.org>

Author: miss-islington

Lib/test/test_venv.py

@@ -594,7 +594,9 @@ def test_zippath_from_non_installed_posix(self):
         # For python built with shared enabled. We need to set
         # LD_LIBRARY_PATH so the non-installed python can find and link
         # libpython.so
-        ld_library_path = os.path.abspath(os.path.dirname(sys.executable))
+        ld_library_path = sysconfig.get_config_var("LIBDIR")
+        if not ld_library_path or sysconfig.is_python_build():
+            ld_library_path = os.path.abspath(os.path.dirname(sys.executable))
         if sys.platform == 'darwin':
             ld_library_path_env = "DYLD_LIBRARY_PATH"
         else: