Re-organize directory structure (#4971)

See discussion in #2491

Co-authored-by: Ivan Levkivskyi <ilevkivskyi@dropbox.com>

stdlib/distutils/spawn.pyi

@@ -0,0 +1,4 @@
+from typing import List, Optional
+
+def spawn(cmd: List[str], search_path: bool = ..., verbose: bool = ..., dry_run: bool = ...) -> None: ...
+def find_executable(executable: str, path: Optional[str] = ...) -> Optional[str]: ...