Fix stdlib/disutils testing (#9734)

stdlib/distutils/util.pyi

@@ -1,8 +1,12 @@
+import sys
 from _typeshed import StrPath, Unused
 from collections.abc import Callable, Container, Iterable, Mapping
 from typing import Any
 from typing_extensions import Literal
 
+if sys.version_info >= (3, 8):
+    def get_host_platform() -> str: ...
+
 def get_platform() -> str: ...
 def convert_path(pathname: str) -> str: ...
 def change_root(new_root: str, pathname: str) -> str: ...